Shitty Gen VIII Speculation:

1. Console: Tentatively Nintendo Switch. As Switch's fate as a handheld remains dubious, I am going to put this as tentative. Edit(13.06.2017): Confirmed to be Switch.
2. Year: 2019-2020. 2019 is if Switch is released in 2017. 2020 is if Nintendo has a real successor to 3DS in 2018.
3. Location basis: From most likely to least likely:

• Spain, Masuda recently made a panel in Spain after X/Y. Spain is also in the south of France, ie. Kalos.
• Italy. Home of Rome, and has been used for other spin-off titles.
• Germany; one of the biggest markets of Pokémon, also has close historical ties to Japan. The train in Kalos goes there.
• China/Taiwan: due to recent localization into Chinese.
• California: Next major VGC arena after Hawaii.

1. Dex structure. Either around 65 Pokémon and 35 new forms, or a 90-100 new species. There will almost certainly going to be new means of providing de-facto evolutions, as well as at least one cross-generational evolutionary addition, due this being an even generation, but we don't know what that will be, just that it won't be Megas, and not an Eeveelution if there is no new type.
2. Type change: With only 25 type combinations remaining, a big change to the way types work should be expected.
3. Ability overhaul: After the overhaul on evolutions and moves, the last things that remain are abilities, types and items. Abilities are more likely to be overhauled for obvious reasons.
4. New field move: After weathers, rooms and terrains, we need something new and sparkly.
5. More overworld encounters: Because we are in 3D (TM).
6. Less evolutions, more forms: Because they sell better.
7. Possible upgrade into 150 TMs: With HMs removed, there is really no reason to keep 100 limit.
8. Pokémon grooming removed: With the move into another hardware, it seems to pointless to keep this.

Dex Speculation:

1. Grass
2. Grass
3. Grass/Rock : Grass starter
4. Fire
5. Fire
6. Fire/Fairy: Fire starter
7. Water
8. Water
9. Water/Ghost or Water/Fighting: Water starter
10. Normal/Flying
11. Normal/Flying or Electric/Flying
12. Normal/Flying or Electric/Flying: Starting bird
13. Bug
14. Bug
15. Bug or Bug/Flying or Bug/Fairy or Bug/Fire: Starting bug
16. Normal
17. Normal or Normal/Electric: Starting rodent
18. Grass/Water
19. Grass/Water: Starting grass
20. Poison/Grass
21. Poison/Grass: Starting grass II
22. Fire/Electric
23. Fire/Electric: Starting fire 
24. Fighting
25. Fighting/Rock: Starting Fighter
26. Electric/Fighting
27. Electric/Fighting: Starting electric
28. Ghost/Water
29. Ghost/Water: Starting Ghost
30. Rock/Ghost: Mid-game Ghost
31. Ground/Water
32. Ground/Water: Mid-game Ground
33. Dark/Normal
34. Dark/Normal: Starting Dark
35. Ice/Normal
36. Ice/Normal: Late-game Ice
37. Water/Steel
38. Water/Steel: Generic fish
39. Steel/Fire
40. Steel/Fire: Late-game Steel
41. Electric/Normal or Electric/Ground: Pikaclone
42. Rock/Fire
43. Rock/Fire: Fossil I
44. Flying/Rock
45. Flying/Rock: Fossil II
46. Psychic/Ground
47. Psychic/Ground: Mid-game Psychic
48. Dark/Poison or Poison/Fighting: Early poison
49. Dark/Poison or Poison/Fighting: Early poison
50. Bug
51. Bug: Generic mid-game bug. We need more pure bugs.
52. Electric/Dragon: Generic standalone
53. Fairy/Dragon: Generic standalone
54. Rock: Generic standalone.
55. Flying
56. Flying: Generic gimmick
57. Dragon/Bug
58. Dragon/Bug
59. Dragon/Bug: Pseudo
60. Psychic/Fire
61. Psychic/Water
62. Psychic/Electric: Legendary box trio
63. Ice/Fairy: Mythical 1
64. Dark/Ghost: Mythical 2
65. Steel/Normal: Mythical 3
66. ((Grass + Fire )): Possible Cherrim or Sunflora forme?
67. ((Psychic + Ice)): Possible Jynx or Cresselia forme?
68. (( Rock )): Possible Sudowoodo or Gigalith forme?
69. (( Steel )): Possible Registeel or Klinklang forme?
70. ((Ground )): Possible Donphan forme?
71. (( Bug + Flying )): Possible Ledian or Vivillon forme?
72. ((Bug + Psychic )): Possible Butterfree forme?
73. (( Ice )): Possible Cryogonal forme?
74. ((Ice/Fighting)): Possible Beartic forme?
75. ((Dark + Steel)): Possible Bisharp forme?
76. ((Dragon/Dark)): Possible Haxorus or Druddigon forme?
77. ((Dragon/Water)): Possible Goodra forme?
78. ((Poison/Bug)): Possible Gligar regional forme?
79. (( Bug + Dark)): Possible Accelgor or Ninjask forme?
80. ((Ice + Normal)): Possible regional forme?
81. ((Normal + Grass): Possible regional forme? Sawsbuck forme?
82. ((Water + Ice)): Possible Walrein, Dewgong, Lapras or Cloyster forme?
83. (( Fairy )): Possible regional forme?
84. (( Bug + Ground )): Possible regional forme?
85. (( Ice + Flying )): Possible regional forme ?
86. ((Electric )): Possible Electivire forme?
87. ((Dragon + Psychic )): Possible regional forme?
88. ((Dark + Water)): Possible Crawdaunt or Malamar forme?
89. ((Water )): Possible regional forme?
90. ((Fire )): Possible Magmortar forme?
91. ((Dark)): Possible regional forme?
92. ((Fighting)): Possible Primeape forme?
93. ((Dragon +Flying )): Possible Dragonite or Noivern forme?
94. ((Fighting + Psychic)): Possible regional forme? Or Mienshao or Grumpig forme?
95. ((Psychic+ Ground)): Possible Claydol forme?
96. ((Psychic+ Rock)): Possible Solrock or Lunatone forme? Grumpig forme?
97. ((Dark+ Ground)): Regional variant? Krookodile forme?
98. ((Poison + Dragon)): Regional variant? Arbok or Dragalge forme?
99. ((Ghost )): Mismagius forme? Regional variant?
100. (( Grass )): Meganium forme? Regional variant?

Extra notes:

1. A potentially large dex?: Previous two generations kept the 100+ Pokémon by introducing new forms that are de facto new species, like Megas and Regional forms. However, we currently have 802 Pokémon, and to reach to the next hundred like how the previous generations did, we need at least 98 new Pokémon. It is possible that we might see another 150 like in BW era, but as the next generation is an even one, this seems unlikely.
2. Lots and lots of signature moves and abilities: Which won't amount to anything, but cause issues for a single generation.
3. Another massive egg move update: It is an even generation, so it is bound to happen.
4. Another remake: Not necessarily in this generation, but it is new hardware, so it is bound to happen.
5. Alternate dex speculation:

1. Grass
2. Grass
3. Grass/Psychic : Grass starter
4. Fire
5. Fire
6. Fire/Poison: Fire starter
7. Water
8. Water
9. Water/Rock: Water starter
10. Normal/Flying
11. Normal/Flying or Fairy/Flying
12. Normal/Flying or Fairy/Flying: Starting bird
13. Grass/Fighting:
14. Grass/Fighting: Starting Grass
15. Grass/Ground:
16. Grass/Ground: Starting Grass
17. Ground
18. Ground: Starting Ground
19. Dark:
20. Dark/Ground: Starting Dark
21. Grass: Generic standalone
22. Bug
23. Bug
24. Bug/Flying: Generic bug
25. Fighting
26. Fighting/Rock: Generic Fighting
27. Poison/Bug
28. Poison/Bug: Generic Poison
29. Water
30. Water: Generic fish
31. Ground/Water
32. Ground/Water: Generic mud mon.
33. Normal/Electric
34. Normal/Electric: Generic electric
35. Psychic/Ice: Generic standalone
36. Fairy/Psychic: Generic standalone
37. Flying/Psychic
38. Flying/Psychic: Generic Psychic
39. Fairy
40. Fairy: Generic Fairy
41. Fairy/Fire
42. Fairy/Fire: Generic Fire
43. Ice/Fighting: Generic standalone
44. Steel
45. Steel: Generic Steel
46. Ice/Rock: Generic standalone
47. Ice/Normal
48. Ice/Normal: Generic late-game Ice
49. Grass/Rock: Generic standalone
50. Rock/Dark: 
51. Rock/Dark: Generic fossil I
52. Steel/Rock:
53. Steel/Rock: Generic fossil II
54. Ghost
55. Ghost: Generic Ghost
56. Bug/Fairy: Generic standalone
57. Dragon
58. Dragon
59. Dragon/Steel: Pseudo
60. Fairy/Fighting
61. Ghost/Flying
62. Dragon/Normal: Legendary trio
63. Fairy/Grass: Mythical I
64. Rock/Ghost: Mythical II
65. Fighting/Psychic: Mythical III

Edit (23.11.2016):

Some thoughts on the future of the types:

Bug: Generally even generations do not introduce a bulk of Bug-types, that role is traditionally given to odd generations. So while Bug is now a secondary typing rather than a primary only one, it is not too likely that there is going to be a large boost on Bug-types.

Possible Bug types that can be improved include: Butterfree, Parasect, Venomoth, Ledian, Forretress, Shuckle, Dustox, Ninjask, etc.

Dark: Same as Bug, most of the Dark-types tend to be released in odd generations. However, Dark-type has gained as much as boosts as Fairy, Fighting and Psychic, so it is possible that Dark-type might get a trio or a quartet of legendaries.

Possible Dark types that can be improved include: Umbreon, Mightyena, Shiftry, Carvanha, Crawdaunt, etc.

Dragon: Dragons tend to get major boosts in even generations than in odd generations. So a lot more Dragons or Dragon moves will be introduced.

However, Dragon only has one type left for completing the whole type chart, which is Dragon/Bug.

Possible Dragon types that can be improved include: Dragonite, Kingdra, Flygon, Haxorus, Druddigon etc. 

Electric: Electric almost never has a large introduction in even generations, so one should not expect much.

Possible Electric types that can be improved include: Jolteon, Lanturn, Luxray, Zebstrika, Galvantula etc.

Fairy: Fairy has been getting a huge boost due to being a new type, so that might continue for a while. +10 more Fairies can work.

Possible Fairy types that can be improved include: Granbull, Whimsicott, Florges, Aromatisse, Slurpuff etc.

Fighting: Fighting generally doesn't get much distribution in even generations. But it gets new unique types.

The remaining types are: Electric/Fighting, Fighting/Ground, Fairy/Fighting.

Fire: Much like Fighting, Fire generally doesn't get much distribution in even generations. But it gets new unique types.

The remaining types are: Fire/Grass, Fire/Fairy, Fire/Ice.

Flying: Oddly enough, Flying gets a wide distribution in even generations, but there are no Flying type combinations that remain to be used. The only things remaining are:

Unique types like Poison/Flying, Fairy/Flying.

And primary Flying Pokémon.

Ghost: Ghosts post-Gen II have gained a decent representation in even gens, though odd gens tend to introduce more. The remaining types are Ghost/Normal and Ghost/Rock.

Possible Ghost types that can be improved include: Drifblim, Spiritomb, Froslass, Jellicent, Chandelure, Golurk etc.

Grass: Grass-types tend to get a fair amount of Pokémon in even generations, though not at the level of odd generations. Currently, the only remaining type combination is Grass/Fire, but other rare types can see more distribution instead, like Grass/Rock, Grass/Normal, Grass/Ground and Grass/Electric.

Ground: Ground-types tend to get a fair amount of Pokémon n even generations, except in Gen VII. Fairy/Ground and Fighting/Ground are the only types remaining.

Possible Ground types that can be improved include: Quagsire, Donphan, Ninjask, Flygon, Whiscash, Claydol, etc.

Ice: Ice type also get a fair amount of new Pokémon in even generations. Ice remains a rare-type however, so there are still a lot of that can be done with it.

Pokémon that can be improved are: Dewgong, Cloyster, Lapras, Articuno, Froslass, Walrein, Regice etc.

Normal: Normal generally gets pure-Normal types and Normal/Flying mons in even generations, with a few dual types thrown in. Ice/Normal, Bug/Normal, Rock/Normal and Poison/Normal remain unused.

Poison: Poison-types generally don't get much from even generations, except in DP. As Poison remains a rare type, there are a lot of stuff that can be introduced.

Possible Pokémon that can be improved are: Venomoth, Tentacruel, Weezing, Dustox, Gulpin, Skuntank etc.

Psychic: Psychic generally gets a good distribution in even generations. The only remaining Psychic combinations are Poison/Psychic and Bug/Psychic.

Rock: Rock generally gets a mediocre distribution in even generations. There are only two Rock-type combinations left, which are Rock/Normal and Rock/Ghost.

Most notably, new Fossils should be expected.

Possible Pokémon that can be improved are: Kabutops, Omastar, Shuckle, Cradily, Armaldo, Relicanth, Regirock, etc.

Steel: Steel generally gets a good distribution in even generations besides Gen VI, but as Steel is getting rarer, it is unlikely that we will see much new stuff.

Possible Pokémon that can be improved are: Forretress, Skarmory, Registeel, Jirachi, Empoleon, Bastiodon, Wormadam Trash, Bronzong etc.

Water: Literally all the types have been used for Water, so the real focus would be in rare type combinations and Water as a secondary typing.

--Everything else:

-Regional Bug is likely going to be Bug/Flying.

-Pseudo-legendary, if it is a Dragon, can only have quad weakness if it is Grass/Dragon, as everything else has been used. It is likely going to be a rare type instead, however.

-Starters will likely have dual typing as even generations tend to do that. 

-There is likely going to be only one or two early Grass-types.

-Pikaclone would likely either Electric/Ground or Electric/Fighting.

-The fishing rod Pokémon is likely going to be pure Water as usual.
-Dragon, Ice and Rock all have low amount of moves, so they can see some boosts.

Edit (09.12.16):
-Assuming there is an Eeveelution, I suspect three possibilities:
--A counterpart to Sylveon
--A homage to Dusk Stone.
--A new type is introduced and it is that.
-Possible alternate forms from previous generations, based off their disparity.
-- Bug: Possibly N/A.
--Dark: Possibly Gen II and IV.
--Dragon: Possibly Gen IV.
--Electric: Possibly Gen IV.

Edit (27.12.16):
--Fairy: Possibly Gen V.
--Poison: Possibly Gen II and Gen VI.
--Fire: Possibly Gen IV.
--Ice: Almost any region really.
--Ground: Possibly Gen V.
--Bug: Possibly for Gen VI.
--Fighting: Possibly for Gen II.
--Steel: Possibly for Gen VI.
--Normal: N/A
-Water: N/A
-Flying : N/A
-Ghost: Possibly for Gen II.
-Grass: Possibly for Gen II.
-Psychic: Possibly Gen II and IV.
-Rock: Possibly for Gen II.

Old Species for the Regional Pokédex.:

Species that haven't reappeared before:

1. Munna
2. Musharna
3. Pidove
4. Tranquill
5. Unfezant
6. Blitzle
7. Zebstrika
8. Drilbur
9. Excadrill
10. Tympole
11. Palpitoad
12. Seismitoad
13. Sewaddle
14. Swadloon
15. Leavanny
16. Darumaka
17. Darmanitan
18. Maractus
19. Yamask
20. Cofagrigus
21. Minccino (Appeared in USUM)
22. Cinccino (Appeared in USUM)
23. Frillish (Appeared in USUM)
24. Jellicent (Appeared in USUM)
25. Joltik
26. Galvantula
27. Klink
28. Klang
29. Klinklang
30. Tynamo
31. Eelektrik
32. Eelektross
33. Elgyem (Appeared in USUM)
34. Beheeyem (Appeared in USUM)
35. Bouffalant
36. Larvesta (Appeared in USUM)
37. Volcarona (Appeared in USUM)
38. Bunnelby
39. Diggersby
40. Scatterbug
41. Spewpa
42. Vivillon
43. Litleo (Appeared in USUM)
44. Pyroar (Appeared in USUM)
45. Flabébé (Appeared in USUM)
46. Floette (Appeared in USUM)
47. Florges (Appeared in USUM)
48. Skiddo
49. Gogoat
50. Furfrou (Appeared in USUM)
51. Espurr
52. Meowstic
53. Honedge
54. Doublade
55. Aegislash
56. Spritzee
57. Aromatisse
58. Swirlix
59. Slurpuff
60. Inkay (Appeared in USUM)
61. Malamar (Appeared in USUM)
62. Binacle
63. Barbaracle
64. Skrelp (Appeared in USUM)
65. Dragalge (Appeared in USUM)
66. Clauncher (Appeared in USUM)
67. Clawitzer (Appeared in USUM)
68. Helioptile
69. Heliolisk
70. Tyrunt (Appeared in USUM)
71. Tyrantrum (Appeared in USUM)
72. Amaura (Appeared in USUM)
73. Aurorus (Appeared in USUM)
74. Hawlucha (Appeared in USUM)
75. Dedenne (Appeared in USUM)
76. Pumpkaboo
77. Gourgeist
78. Bergmite
79. Avalugg
80. Noibat (Appeared in USUM)
81. Noivern (Appeared in USUM)

Species that reappeared once:

1. Teddiursa-Ursaring (does not appear in Kanto, Hoenn, Sinnoh, New Unova or Alola Dexes)
2. Makuhita-Hariyama (does not appear in Kanto, Hoenn, Sinnoh, New Unova or Alola Dexes) (Appeared in USUM)
3. Mawile (does not appear in Kanto, Johto, Sinnoh, New Unova or Alola Dexes) (Appeared in USUM)
4. Lotad-Lombre-Ludicolo (does not appear in Kanto, Johto, Sinnoh, New Unova or Alola Dexes)
5. Shuppet-Banette (does not appear in Kanto, Johto, Sinnoh, New Unova or Alola Dexes) (Appeared in USUM)
6. Clamperl-Huntail-Gorebyss (does not appear in Kanto, Johto, Sinnoh, New Unova or Alola Dexes) (Appeared in USUM)
7. Starly-Staravia-Staraptor (does not appear in Kanto, Johto, Hoenn, New Unova or Alola Dexes)
8. Burmy-Wormadam-Mothim (does not appear in Kanto, Johto, Hoenn, New Unova or Alola Dexes)
9. Bidoof-Bibarel (does not appear in Kanto, Johto, Hoenn, New Unova or Alola Dexes)
10. Pachirisu (does not appear in Kanto, Johto, Hoenn, New Unova or Alola Dexes)
11. Bronzor-Bronzong (does not appear in Kanto, Johto, Hoenn, Kalos or Alola Dexes)
12. Buneary-Lopunny (does not appear in Kanto, Johto, Hoenn, Kalos or Alola Dexes) (Appeared in USUM)
13. Chatot (does not appear in Kanto, Johto, Hoenn, New Unova or Alola Dexes)
14. Stunky-Skuntank (does not appear in Kanto, Johto, Hoenn, New Unova or Alola Dexes)
15. Snover-Abomasnow (does not appear in Kanto, Johto, Hoenn, New Unova or Alola Dexes)
16. Hippopotas-Hippowdon (does not appear in Kanto, Johto, Hoenn, New Unova or Alola Dexes)
17. Rotom (does not appear in Kanto, Johto, Hoenn, New Unova or Alola Dexes)
18. Patrat-Watchog (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
19. Purrloin-Liepard (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
20. Woobat-Swoobat (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
21. Timburr-Gurdurr-Conkeldurr (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
22. Throh (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
23. Sawk (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
24. Basculin (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes) (Appeared in USUM)
25. Dwebble-Crustle (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
26. Sigilyph (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
27. Zorua-Zoroark(does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes) (Appeared in USUM)
28. Foongus-Amoonguss (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
29. Karrablast-Escavalier (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
30. Shelmet-Accelgor (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
31. Solosis-Duosion-Reuniclus (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
32. Gothita-Gothorita-Gothitelle (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
33. Stunfisk (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
34. Litwick-Lampent-Chandelure (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
35. Cubchoo-Beartic (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
36. Heatmor (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
37. Durant (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
38. Druddigon(does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes) (Appeared in USUM)
39. Cryogonal (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
40. Pawniard-Bisharp (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes) (Appeared in USUM)
41. Deino-Zweilous-Hydreigon (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
42. Golett-Golurk (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes) (Appeared in USUM)
43. Ferroseed-Ferrothorn (does not appear in Kanto, Johto, Hoenn, Sinnoh or Alola Dexes)
44. Venonat-Venomoth(does not appear in Hoenn, Sinnoh or New Unova, Kalos, Alola Dexes)
45. Seel-Dewgong(does not appear in Hoenn, Sinnoh or New Unova, Kalos, Alola Dexes) (Appeared in USUM)
46. Krabby-Kingler(does not appear in Hoenn, Sinnoh or New Unova, Kalos, Alola Dexes)
47.  (Tyrogue-)Hitmonchan-Hitmonlee(-Hitmontop)(does not appear in Hoenn, Sinnoh or New Unova, Kalos, Alola Dexes)
48. Omanyte-Omastar(does not appear in Hoenn, Sinnoh or New Unova, Kalos, Alola Dexes) (Appeared in USUM)
49. Kabuto-Kabutops(does not appear in Hoenn, Sinnoh or New Unova, Kalos, Alola Dexes) (Appeared in USUM)
50. Mew(does not appear in Hoenn, Sinnoh or New Unova, Kalos, Alola Dexes)
51. Natu-Xatu(does not appear in Kanto, Sinnoh or New Unova, Kalos or Alola Dexes) (Appeared in USUM)
52. Phanpy-Donphan(does not appear in Kanto, Sinnoh or New Unova, Kalos or Alola Dexes)
53. Aipom(-Ambipom)(does not appear in Kanto, Hoenn or New Unova, Kalos or Alola Dexes) (Appeared in USUM)
54. Unown(does not appear in Kanto, Hoenn or New Unova, Kalos or Alola Dexes)
55. Togepi-Togetic(-Togekiss)(does not appear in Kanto, Hoenn or New Unova, Kalos or Alola Dexes)
56. Duskull-Dusclops(-Dusknoir)(does not appear in Kanto, Johto or New Unova, Kalos or Alola Dexes)
57. Sunkern-Sunflora(does not appear in Kanto, Hoenn or Sinnoh, Kalos or Alola Dexes)
58. Baltoy-Claydol(does not appear in Kanto, Johto or Sinnoh, Kalos or Alola Dexes) (Appeared in USUM)
59. Numel-Camerupt(does not appear in Kanto, Johto or Sinnoh, Kalos or Alola Dexes)
60. Spheal-Sealeo-Walrein(does not appear in Kanto, Johto or Sinnoh, Kalos or Alola Dexes)
61. Slakoth-Vigoroth-Slaking(does not appear in Kanto, Johto or Sinnoh, Kalos or Alola Dexes)
62. Fletchling-Fletchinder-Talonflame
63. Pancham-Pangoro
64. Eevee-Sylveon
65. Carbink
66. Goomy-Sliggoo-Goodra
67. Klefki
68. Phantump-Trevenant
69. Zygarde 

Species that don't appear in Kalos or Alola dexes:

1. Koffing-Weezing(does not appear in Sinnoh Dex, Kalos Dex or Alola Dex)
2. Tangela(-Tangrowth)(does not appear in Hoenn Dex, Kalos Dex or Alola Dex)
3. Ponyta-Rapidash(does not appear in Hoenn or New Unova, Kalos or Alola Dexes)
4. Girafarig(does not appear in Kanto or New Unova, Kalos or Alola Dexes)

This current list gives us a nice collection of stuff to work with. Not only do they reduce the need for species that are not too unique, they also have a neat type distribution. Most lacking in this scheme is not a certain archetype, but a lack of three-stagers. There will likely be token additions from Alola as well, but it is difficult to determine what.

1. 
   

Edit (04.01.2017): On Species that have recently gained prominence:

1. Granbull: With the introduction of Fairy-type, Granbull has become the go-to physical Fairy, in spite-of Azumarill. This might suggest a future buff.
2. Gastrodon: Former Champion Pokémon, Gastrodon regained its prominence as one of Hapu's Pokémon, which can imply a future buff.
3. Mismagius: Appearing in both Anabel and Phoebe's team, Mismagius might get a future buff besides new moves.
4. Leafeon: Replacing Jolteon in SuMo, Leafeon might be ready for future moves.
5. Hypno: After being put into freezer for two generations, Hypno regained some prominence as Faba's signature mon.
6. Primeape: Being used by both Hala and Evelyn, Primeape gained some prominence as an acceptable Pokémon.
7. Skarmory: The ol' reliable, this guy regained its status as a late-game Pokémon by reentering Pokémon League after being thrown into early Chateau trainers.
8. Carbink: Though treated as a first stager in-game, this guy also appears in Pokémon League with both Steven and Olivia.
9. Relicanth: Appearing on a prominent trainer for the first time, this guy is part of Olivia's team.
10. Delibird: Because GF realized this guy exists, we might see more from it besides Drill Peck.
11. Lilligant: Having gained some prominence, this gal might some neat buffs in the future.
12. Tauros: Since it is a thing again, it might get something nifty.

On moves and other stuff for Types:

1. Bug: Bug-type is currently missing in Special and Status moves. Bug-type is also desperate for new Trainer Classes for Western Regions, since just slapping Bug onto powerful trainers is not going to stick for a long time.
2. Dark: Dark-type currently needs more emphasis on Special and powerful physical moves. It also needs another type specialist besides generic evil teams and Delinquent/Street Thug.
3. Dragon: Dragon needs more Status and Special moves. It also needs more type specialists besides Ace Trainers/Veterans and Dragon Tamers.
4. Electric: Electric needs more Physical moves and more type specialists that are common.
5. Fairy: It just needs more moves in general.
6. Fighting: It needs more Special and Status moves. It would also enjoy more classes for future proofing.
7. Fire: Fire-type needs more Status moves.It would also enjoy more trainer archetypes.
8. Flying: It just needs more moves, primarily Status and Special., but also a few Physical moves for other types. It would also enjoy more type specialists for future proofing.
9. Ghost: It just needs more moves, primarily Physical and high powered. It would also enjoy future trainer classes for future proofing.
10. Grass: Actually it is currently very nice. It would just need more standard moves, particularly for in-between and other types' coverage. More type specialists would also be nice, particularly an E4.
11. Ground: It needs more Special and Status moves. And more type specialist classes.
12. Ice: It needs more Status and Physical moves. And more type specialist classes.
13. Normal: It needs more Special moves. More type specialists and an E4 would also be nice. 
14. Poison: It needs more moves in general, particularly late-game and early-game moves. More type specialists besides generic evil teams would also be nice, so would another major type expert like a Gym Leader, E4 or ideally, a Champion.
15. Psychic: It just needs more attacking moves, particularly Physical. It would also enjoy more type specialists besides Psychic, and a Champion.
16. Rock: It needs more Special moves.It would also enjoy more type specialists.
17. Steel: It needs more moves in general. It would also enjoy a real type specialist class.
18. Water: It needs more moves in general. It would also enjoy more terrestrial specialists.

Gym Leader and E4 wishlist.

Gym Leaders:

1. Dark
2. Ground
3. Ice
4. Psychic
5. Steel
6. Bug
7. Fire
8. Rock

Elite Four:

1. Fairy
2. Poison
3. Electric
4. Grass

Champion: Normal

Villain Team: Dragon

Speculation:

Gym Leaders:

1. Normal
2. Dark
3. Bug
4. Fighting
5. Ice
6. Electric
7. Dragon
8. Steel

Elite Four:

1. Grass
2. Poison
3. Fire
4. Fairy

Champion: Varied or Psychic
Villain team: Rock

Edit(13.01.2017): On legendaries, I have two guesses:

-A repeat of Black/White: A trio that has the common matching type of the legendaries plus the types of the sub-legendaries after Winged Mirages, which are the Legendary Beasts. So, Fire/Psychic, Water/Psychic and Electric/Psychic can work.

-A repeat of R/S/E: Going for another Earth/Sky/Sea theme, these legendaries could be based off Grass, Bug and Poison. Alternatively, they can be Grass/Electric/Dragon to allude to Weather Trio.

-A repeat of R/G/B: Going for Fire/Grass/Water of the classic trio, these legendaries could continue the color theme of Sun/Moon. Though I'm primarily listing this because of Kiawe and Mallow.

-LolSina&Dexio: Ice and Psychic, would be primary type duo. Going for a Special Attack theme, the third type could be Electric and/or Dragon, but if that's too obvious it can be Bug instead.

For Mythicals I expect Fairy and Ghost theme to continue.

For sub-legends, I would have to go for a type basis:

Grass: Virizion, Tapu Bulu, (Kartana)
Fire: Entei, Moltres, Heatran, (Blacephalon)
Ground: Landorus
Ice: Articuno, Regice
Normal: Regigigas
Rock: Regirock, (Nihilego) (Stakataka)
Water: Suicune, Tapu Fini
Fairy: Guardian Deities
Psychic: Legendary Pixies, Lati Twins, Cresselia, Tapu Lele
Dragon: Lati twins, (Guzzlord) (Naganadel)
Dark: (Guzzlord)
Poison: (Nihilego)(Poipole, Naganadel)
Electric: Zapdos, Raikou, Tapu Koko, (Xurkitree)
Steel: Registeel, Cobalion, (Kartana), (Celesteela) (Stakataka)
Fighting: Swords of Justice, (Pheromosa), (Buzzwole)
Flying: Winged Mirages, Kami trio
Ghost: N/A (Blacephalon)

I don't think we will see more sub-legendaries next generation, but if we do, Flying, Fighting, Psychic, Electric, Fire are overdone.Water has too many Mythicals, and Steel is full enough.

A common shared type can be Dark-type, and the other types can be Poison, Rock and Ice or Grass.

Edit(15.01.2017): On items:

1.There seems to be a larger focus on consumables over everything else. I expect this to continue on, though we already covered Terrain related consumables.

2.For permanent items, it is possible that we might get something related to Safeguard. Other than that, some more critical hit related stuff would be nice.

I don't expect much game changing items as whatever is announced will be behind the gimmick of this generation.

Edit(12.02.2017):

-On starters types' we have:

Dragon: Fire and Grass
Ground: Water and Grass
Fighting: Fire and Grass
Dark: Water and Fire
Flying: Fire (and Grass)
Bug: N/A
Rock: N/A
Ghost: Grass
Steel: Water
Psychic: Fire
Normal: N/A
Ice: N/A
Electric: N/A
Poison: Grass
Fairy: Water

--Early rodent types:

Normal/Ground
Normal/Water
Dark/Normal

--Early bird types:

Fire/Flying
Water/Flying

--Early grass types:

Grass/Poison
Grass/Flying
Bug/Grass
Grass/Dark
Grass/Fairy
Water/Grass

--Early bug types:

Bug/Flying
Bug/Poison
Bug/Steel
Bug/Ground
Bug/Grass
Bug/Steel
Bug/Electric
Bug/Fairy
Water/Bug-Bug/Water

25.04.17: A new trade-only evolution item is to be expected:

Gen II:

Up-Grade: Porygon2, Normal
Dragon Scale: Kingdra, Water/Dragon
King's Rock: Politoed, Slowking, Water, Water/Psychic
Metal Coat: Scizor, Steelix, Bug/Steel, Steel/Ground

Gen III:

Deep Sea Scale, Fang: Gorebyss, Huntail

Gen IV:

Dubious Disc: Porygon-Z, Normal
Protector: Rhyperior, Ground/Rock
Reaper Cloth: Dusknoir, Ghost
Electirizer: Electivire, Electric
Magmarizer: Magmortar, Fire

Gen V:

Prism Scale: Milotic, Water

Gen VI:

Sachet: Aromatisse, Fairy
Whipped Dream: Slurpuff, Fairy

Others:

Gen IV:

Razor Fang: Gliscor, Ground/Flying
Razor Claw: Weavile, Dark/Ice
Oval Stone: Chansey, Normal

Poison, Fighting, Grass are missing.
Dedicated Bug, Psychic, Ground, Ice, Dark, Flying are missing.

Edit (03.06.2017):
Some guesses on BSTs:

1. Grass starter: As the previous starter was a dual-offense Pokémon, this one will likely be either a Specially oriented tank, Specially oriented wall or a Specially oriented speedster.
2. Water starter: As the previous starter was a Special tank, this one will likely be either a Physical offense Pokémon, or a fast wall.
3. Fire starter: As the previous starter was a Physical tank, this one will likely be either a Physical sweeper or a fast wall.
4. Regional bird: As the previous bird was a Physical tank, this one will likely be either Specially oriented or a fast wall.
5. Starting bug: Quiver Dance spammers tend to be the same, but this one might be Special Defense oriented.
6. Regional rodents: Rodents tend to be the same, but this one might be a fast wall.
7. Starting grass: As the previous one was Physically oriented, this one will likely be either defensive or Specially oriented. It's opposite, if there is any would be the reverse.

Edit (09.06.2017):

• Since there is no DPPt remake 7th gen, this will likely be where it occurs. Assuming we are still in 3DS, of course.
• Necrozma forms will likely reach around 716 BST, so the next third legendary will likely reach to the base Arceus or more likely beyond. But since there won't be third version, it will likely not achieve that here.
• Games will likely match RSE and ORAS, so either the main trio or a sub-trio will continue to next gen. Similarly, likely all legendaries will have an updated form, not just the main two or third guy.
• In continuation with this, the next major gimmick will likely focus on Abilities.
• In keeping with the trend, the third legendary will likely have around 580 BST and reach around 720 or 780+.
• More Berries, likely ones focused on Accuracy and Evasion.

Edit(15.06.2017):

-Notes on cross generational updates:

--Cross-generational additions:

Gen II: 7 babies, 11 evolutions(6 main, 5 side)

Gen III: 2 babes,

Gen IV: 7 babies, 22 evolutions (18 main, 4 side)

Gen V: N/A

Gen VI: 46 Megas(+2 alt Megas), 1 side, 2 Primals

Gen VII: 13 Alolan forms (10 full lines, 3 side evos)

Looking at this one would expect a massive amount of Megas, but since that mechanic isn't coming back, we can't say anything until we see what replaces it. Babies can also return.

For stat retcons

Gen 6: 29, almost exclusively third stages.

Gen 7: 26, primarily second stages.

This likely means Gen 8 will introduce about 23 retcons, primarily for single stage Pokémon. However, without cross-gen evos, that number might increase.

Edit(21.07.2017): Rough BST ranges for dex speculation:

1. Grass
2. Grass
3. Grass/Rock : Grass starter, around 530-535 BST
4. Fire
5. Fire
6. Fire/Fairy: Fire starter, around 530-535 BST
7. Water
8. Water
9. Water/Ghost or Water/Fighting: Water starter, around 530-535 BST
10. Normal/Flying
11. Normal/Flying or Electric/Flying
12. Normal/Flying or Electric/Flying: Starting bird, around 485-499 BST.
13. Bug
14. Bug
15. Bug or Bug/Flying or Bug/Fairy or Bug/Fire: Starting bug, around 410-500 BST
16. Normal
17. Normal or Normal/Electric: Starting rodent, around 410-425 BST
18. Grass/Water
19. Grass/Water: Starting grass, around 480 BST
20. Poison/Grass
21. Poison/Grass: Starting grass II, around 480 BST
22. Fire/Electric
23. Fire/Electric: Starting fire, around 500 BST 
24. Fighting
25. Fighting/Rock: Starting Fighter, around 490-500 BST
26. Electric/Fighting
27. Electric/Fighting: Starting electric, around 480-490 BST
28. Ghost/Water
29. Ghost/Water: Starting Ghost, around 480 BST
30. Rock/Ghost: Mid-game Ghost, around 490 BST
31. Ground/Water
32. Ground/Water: Mid-game Ground, around 500 BST
33. Dark/Normal
34. Dark/Normal: Starting Dark, around 450 BST
35. Ice/Normal
36. Ice/Normal: Late-game Ice, around 500 BST
37. Water/Steel
38. Water/Steel: Generic fish, around 480 BST
39. Steel/Fire
40. Steel/Fire: Late-game Steel, around 520 BST
41. Electric/Normal or Electric/Ground: Pikaclone, around 435 BST
42. Rock/Fire
43. Rock/Fire: Fossil I, around 521 BST
44. Flying/Rock
45. Flying/Rock: Fossil II, around 521 BST
46. Psychic/Ground
47. Psychic/Ground: Mid-game Psychic, around 480 BST
48. Dark/Poison or Poison/Fighting: Early poison
49. Dark/Poison or Poison/Fighting: Early poison, around 480 BST
50. Bug
51. Bug: Generic mid-game bug. We need more pure bugs., around 470 BST
52. Electric/Dragon: Generic standalone, around 490 BST
53. Fairy/Dragon: Generic standalone, around 490 BST
54. Rock: Generic standalone., around 480 BST
55. Flying
56. Flying: Generic gimmick, around 480 BST
57. Dragon/Bug
58. Dragon/Bug
59. Dragon/Bug: Pseudo, around 600 BST
60. Psychic/Fire
61. Psychic/Water
62. Psychic/Electric: Legendary box trio, around 680 BST
63. Ice/Fairy: Mythical 1
64. Dark/Ghost: Mythical 2
65. Steel/Normal: Mythical 3, around 600 BST
66. ((Grass + Fire )): Possible Cherrim or Sunflora forme?
67. ((Psychic + Ice)): Possible Jynx or Cresselia forme?
68. (( Rock )): Possible Sudowoodo or Gigalith forme?
69. (( Steel )): Possible Registeel or Klinklang forme?
70. ((Ground )): Possible Donphan forme?
71. (( Bug + Flying )): Possible Ledian or Vivillon forme?
72. ((Bug + Psychic )): Possible Butterfree forme?
73. (( Ice )): Possible Cryogonal forme?
74. ((Ice/Fighting)): Possible Beartic forme?
75. ((Dark + Steel)): Possible Bisharp forme?
76. ((Dragon/Dark)): Possible Haxorus or Druddigon forme?
77. ((Dragon/Water)): Possible Goodra forme?
78. ((Poison/Bug)): Possible Gligar regional forme?
79. (( Bug + Dark)): Possible Accelgor or Ninjask forme?
80. ((Ice + Normal)): Possible regional forme?
81. ((Normal + Grass): Possible regional forme? Sawsbuck forme?
82. ((Water + Ice)): Possible Walrein, Dewgong, Lapras or Cloyster forme?
83. (( Fairy )): Possible regional forme?
84. (( Bug + Ground )): Possible regional forme?
85. (( Ice + Flying )): Possible regional forme ?
86. ((Electric )): Possible Electivire forme?
87. ((Dragon + Psychic )): Possible regional forme?
88. ((Dark + Water)): Possible Crawdaunt or Malamar forme?
89. ((Water )): Possible regional forme?
90. ((Fire )): Possible Magmortar forme?
91. ((Dark)): Possible regional forme?
92. ((Fighting)): Possible Primeape forme?
93. ((Dragon +Flying )): Possible Dragonite or Noivern forme?
94. ((Fighting + Psychic)): Possible regional forme? Or Mienshao or Grumpig forme?
95. ((Psychic+ Ground)): Possible Claydol forme?
96. ((Psychic+ Rock)): Possible Solrock or Lunatone forme? Grumpig forme?
97. ((Dark+ Ground)): Regional variant? Krookodile forme?
98. ((Poison + Dragon)): Regional variant? Arbok or Dragalge forme?
99. ((Ghost )): Mismagius forme? Regional variant?
100. (( Grass )): Meganium forme? Regional variant?

OR

1. Grass
2. Grass
3. Grass/Psychic : Grass starter, around 530-535
4. Fire
5. Fire
6. Fire/Poison: Fire starter, around 530-535
7. Water
8. Water
9. Water/Rock: Water starter, around 530-535
10. Normal/Flying
11. Normal/Flying or Fairy/Flying
12. Normal/Flying or Fairy/Flying: Starting bird, around 485-499
13. Grass/Fighting:
14. Grass/Fighting: Starting Grass, around 480
15. Grass/Ground:
16. Grass/Ground: Starting Grass, around 480
17. Ground
18. Ground: Starting Ground, around 500
19. Dark:
20. Dark/Ground: Starting Dark, around 450
21. Grass: Generic standalone, around 470
22. Bug
23. Bug
24. Bug/Flying: Generic bug, around 410-500
25. Fighting
26. Fighting/Rock: Generic Fighting, around 490
27. Poison/Bug
28. Poison/Bug: Generic Poison, around 480
29. Water
30. Water: Generic fish, around 480
31. Ground/Water
32. Ground/Water: Generic mud mon., around 480
33. Normal/Electric
34. Normal/Electric: Generic electric, around 480
35. Psychic/Ice: Generic standalone, around 470
36. Fairy/Psychic: Generic standalone, around 470
37. Flying/Psychic
38. Flying/Psychic: Generic Psychic, around 480
39. Fairy
40. Fairy: Generic Fairy, around 480
41. Fairy/Fire
42. Fairy/Fire: Generic Fire, around 500
43. Ice/Fighting: Generic standalone, around 480
44. Steel
45. Steel: Generic Steel, around 500
46. Ice/Rock: Generic standalone, around 475
47. Ice/Normal
48. Ice/Normal: Generic late-game Ice, around 500
49. Grass/Rock: Generic standalone, around 480
50. Rock/Dark: 
51. Rock/Dark: Generic fossil I, around 521
52. Steel/Rock:
53. Steel/Rock: Generic fossil II, around 521
54. Ghost
55. Ghost: Generic Ghost, around 490
56. Bug/Fairy: Generic standalone, around 490
57. Dragon
58. Dragon
59. Dragon/Steel: Pseudo, around 600
60. Fairy/Fighting
61. Ghost/Flying
62. Dragon/Normal: Legendary trio, around 680
63. Fairy/Grass: Mythical I
64. Rock/Ghost: Mythical II
65. Fighting/Psychic: Mythical III, around 600

Possible HA additions:

Gastly-line: Infiltrator.

Furfrou: Cute Charm or Trace

Ferroseed: Anticipation

Turtonator: Aftermath

Groudon, Rayquaza, Kyogre: Pressure.

Edit(02.08.2015):

Type combinations that have not reappeared for two generations:

1. Poison
2. Water/Flying--Flying/Water
3. Ground/Flying--Flying/Ground
4. Ground/Dark--Dark/Ground
5. Normal/Grass--Grass/Normal
6. Water/Fighting---Fighting/Water
7. Water/Ghost--Ghost/Water
8. Dark/Steel--Steel/Dark
9. Ground/Electric--Electric/Ground
10. Rock/Fighting--Fighting/Rock
11. Dragon/Ice--Ice/Dragon
12. Bug/Grass-Grass/Bug

Type combinations that have not reappeared for three generations:

1. Rock/Ground--Ground/Rock
2. Rock/Steel-Steel/Rock
3. Bug/Rock--Rock/Bug
4. Electric/Water-Water/Electric
5. Ice/Ground--Ground/Ice
6. Bug/Ground--Ground/Bug
7. Water/Dragon--Dragon/Water
8. Dark/Ice--Ice/Dark
9. Fairy/Flying--Flying/Fairy
10. Normal/Water--Water/Normal
11. Ghost/Dragon--Dragon/Ghost
12. Steel/Dragon--Dragon/Steel
13. Fire/Steel--Steel/Fire
14. Water/Steel--Steel/Water
15. Grass/Ground--Ground/Grass
16. Electric/Ghost--Ghost/Electric
17. Electric/Fire--Fire/Electric
18. Electric/Grass--Grass/Electric
19. Electric/Ice--Ice/Electric
20. Ice/Ghost--Ghost/Ice
21. Poison/Fighting--Fighting/Poison

Type combinations that have not reappeared for four generations:

1. Water/Ice--Ice/Water
2. Water/Grass--Grass/Water
3. Grass/Dark--Dark/Grass
4. Ground/Psychic--Psychic/Ground
5. Rock/Grass-Grass/Rock
6. Rock/Psychic--Psychic/Rock
7. Bug/Ghost--Ghost/Bug

Type combinations that have not reappeared for five generations:

1. Psychic/Grass--Grass/Psychic
2. Ice/Flying--Flying/Ice
3. Ice/Psychic--Psychic/Ice
4. Fire/Rock--Rock/Fire

Type combinations that have not reappeared for six generations:

1. Poison/Ground--Ground/Poison

Edit(09.08.2017):

The next big thing involving Pikachu can be a few things:

-A gender independent form, such as Cosplay Pikachu being a form change, rather than a specific Pikachu.

-A third ability for the line.

-A defensive Light Ball.

-Light Ball affecting Pichu.

Edit(16.08.2017):
-Possibly a new evolution stone, either one that is type based like a Psychic Stone, or one that is based on a theme like a Twilight Stone or Dream Stone.
-Possible removal of type boosting items besides plates.

Edit(06.09.2017):
Regional Dex Speculation:

Sub-dex 1:

1. Grass Starter
2. Grass Starter
3. Grass Starter
4. Fire Starter
5. Fire Starter
6. Fire Starter
7. Water Starter
8. Water Starter
9. Water Starter
10. Generic Rodent
11. Generic Rodent
12. Patrat
13. Watchog
14. Bidoof
15. Bibarel
16. Generic Bug
17. Generic Bug
18. Generic Bug
19. Scatterbug
20. Spewpa
21. Vivillon
22. Burmy 
23. Mothim
24. Wormadam
25. Generic Bird
26. Generic Bird
27. Generic Bird
28. Pidove
29. Tranquill
30. Unfezant
31. Pichu
32. Pikachu
33. Raichu
34. Generic Electric
35. Generic Electric
36. Generic Pikaclone
37. Pachirisu
38. Togedemaru
39. Generic Fishmon
40. Generic Fishmon
41. Generic Grass
42. Generic Grass
43. Sunkern
44. Sunflora
45. Purrloin
46. Liepard
47. Meowth
48. Persian
49. Generic Fire
50. Generic Fire
51. Generic Water
52. Generic Water
53. Carvanha
54. Sharpedo
55. Krabby
56. Kingler
57. Drowzee
58. Hypno
59. Buneary
60. Lopunny
61. Diglett
62. Dugtrio
63. Generic Dark
64. Generic Dark
65. Stunky
66. Skuntank
67. Glameow
68. Purugly
69. Makuhita
70. Hariyama
71. Timburr
72. Gurdurr
73. Conkeldurr
74. Generic Fighting
75. Generic Fighting
76. Munna
77. Musharna
78. Venonat
79. Venomoth
80. Natu
81. Xatu
82. Abra
83. Kadabra
84. Alakazam
85. Cottonee
86. Whimsicott
87. Growlithe
88. Arcanine
89. Buizel
90. Floatzel
91. Bonsly
92. Sudowoodo
93. Mime Jr.
94. Mr. Mime
95. Spiritomb
96. Aipom
97. Ambipom
98. Durant
99. Heatmor
100. Seel
101. Dewgong
102. Shellder
103. Cloyster
104. Seedot
105. Nuzleaf
106. Shiftry
107. Lotad
108. Lombre
109. Ludicolo
110. Bouffalant
111. Wimpod
112. Golisopod
113. Woobat
114. Swoobat
115. Sigilyph
116. Generic Fairy
117. Generic Fairy
118. Swirlix
119. Slurpuff
120. Spritzee
121. Aromatisse
122. Petilil
123. Lilligant
124. Karrablast
125. Escavalier
126. Shelmet
127. Accelgor
128. Cutiefly
129. Ribombee
130. Gible
131. Gabite
132. Garchomp
133. Regirock
134. Regice
135. Registeel

Sub-dex 2:

1. Lickitung
2. Lickilicky
3. Tauros
4. Miltank
5. Zangoose
6. Seviper
7. Generic Poison
8. Generic Poison
9. Salandit
10. Salazzle
11. Koffing
12. Weezing
13. Skorupi
14. Drapion
15. Tangela
16. Tangrowth
17. Bounsweet
18. Steenee
19. Tsareena
20. Generic Rock
21. Generic Rock
22. Geodude
23. Graveler
24. Golem
25. Nosepass
26. Probopass
27. Roggenrola
28. Boldore
29. Gigalith
30. Rockruff
31. Lycanroc
32. Generic Ground
33. Generic Ground
34. Hippowdon
35. Hippopotas
36. Mudbray
37. Mudsdale
38. Numel
39. Camerupt
40. Golett
41. Golurk
42. Omanyte
43. Omastar
44. Kabuto
45. Kabutops
46. Generic Fossil
47. Generic Fossil
48. Generic Fossil
49. Generic Fossil
50. Generic Psychic
51. Generic Psychic
52. Gothita
53. Gothorita
54. Gothitelle
55. Solosis
56. Duosion
57. Reuniclus
58. Zorua
59. Zoroark
60. Riolu
61. Lucario
62. Togepi
63. Togetic
64. Togekiss
65. Flabébé
66. Floette
67. Florges
68. Elgyem
69. Beheeyem
70. Klefki
71. Klink
72. Klang
73. Klinklang
74. Magnemite
75. Magneton
76. Magnezone
77. Teddiursa
78. Ursaring
79. Generic gimmick
80. General gimmick
81. Tynamo
82. Eelektrik
83. Eelektross
84. Frillish
85. Jellicent
86. Tentacool
87. Tentacruel
88. Clamperl
89. Huntail
90. Gorebyss
91. Mantyke
92. Mantine
93. Larvesta
94. Volcarona
95. Darumaka
96. Darmanitan
97. Magby
98. Magmar
99. Magmortar
100. Elekid
101. Electabuzz
102. Electivire
103. Blitzle
104. Zebstrika
105. Joltik
106. Galvantula
107. Spheal
108. Sealeo
109. Walrein
110. Swinub
111. Piloswine
112. Mamoswine
113. Zubat
114. Golbat
115. Crobat
116. Minior
117. Aerodactyl
118. Hawlucha
119. Doduo
120. Dodrio
121. Voltorb
122. Electrode
123. Pancham
124. Pangoro
125. Stufful
126. Bewear
127. Taillow
128. Swellow
129. Skarmory
130. Jangmo-o
131. Hakamo-o
132. Kommo-o
133. Regigigas
134. Latias
135. Latios

Sub-dex 3:

1. Generic standalone
2. Generic standalone
3. Kecleon
4. Stantler
5. Girafarig
6. Shroomish
7. Breloom
8. Foongus
9. Amoonguss
10. Slowpoke
11. Slowbro
12. Slowking
13. Psyduck
14. Golduck
15. Staryu
16. Starmie
17. Generic Ice
18. Generic Ice
19. Vanillite
20. Vanillish
21. Vanilluxe
22. Cubchoo
23. Beartic
24. Snorunt
25. Glalie
26. Froslass
27. Snover
28. Abomasnow
29. Generic Ghost
30. Generic Ghost
31. Duskull
32. Dusclops
33. Dusknoir
34. Litwick
35. Lampent
36. Chandelure
37. Misdreavus
38. Mismagius
39. Drifloon
40. Drifblim
41. Generic Steel
42. Generic Steel
43. Honedge
44. Doublade
45. Aegislash
46. Ferroseed
47. Ferrothorn
48. Pawniard
49. Bisharp
50. Bronzor
51. Bronzong
52. Baltoy
53. Claydol
54. Lunatone
55. Solrock
56. Ekans
57. Arbok
58. Grimer
59. Muk
60. Gulpin
61. Swalot
62. Trubbish
63. Garbodor
64. Gligar
65. Gliscor
66. Sneasel
67. Weavile
68. Yanma
69. Yanmega
70. Kangaskhan
71. Feebas
72. Milotic
73. Magikarp
74. Gyarados
75. Munchlax
76. Snorlax
77. Porygon
78. Porygon2
79. Porygon-Z
80. Pyukumuku
81. Lapras
82. Budew
83. Roselia
84. Roserade
85. Chatot
86. Amaura
87. Aurorus
88. Tyrunt
89. Tyrantrum
90. Mienfoo
91. Mienshao
92. Phanpy
93. Donphan
94. Onix
95. Steelix
96. Pidgey
97. Pidgeotto
98. Pidgeot
99. Hoothoot
100. Noctowl
101. Oranguru
102. Passimian
103. Cleffa
104. Clefairy
105. Clefable
106. Absol
107. Igglybuff
108. Jigglypuff
109. Wigglytuff
110. Skrelp
111. Dragalge
112. Clauncher
113. Clawitzer
114. Druddigon
115. Drampa
116. Turtonator
117. Dratini
118. Dragonair
119. Dragonite
120. Generic Dragon
121. Generic Dragon
122. Noibat
123. Noivern
124. Goomy
125. Sliggoo
126. Goodra
127. Deino
128. Zweilous
129. Hydreigon
130. Generic Pseudo
131. Generic Pseudo
132. Generic Pseudo
133. Generic Legendary
134. Generic Legendary
135. Generic Legendary

Note: Mythicals appear in the full dex Alola style.

Edit(30.09.2017): Potential stat updates:

1. Bibarel: +10, BST: 410->420.
2. Mothim/Wormadam: +30, BST: 424->454
3. Pachirisu: +30, BST: 405->435
4. Sunflora: +40, BST: 425->465
5. Purugly: +25, BST: 452->477
6. Venomoth: +30, BST: 450->480
7. Sudowoodo: +50, BST: 410->460
8. Dewgong: +30, BST: 475->505
9. Garbodor: +25, BST: 474->499
10. Girafarig: +30, BST: 455->485
11. Stantler: +20, BST: 465->485
12. Aromatisse: +20, BST: 462->482
13. Ludicolo/Shiftry: +10, BST: 480->490
14. Swoobat: +30, BST: 425->455
15. Gothitelle/Reuniclus: +10, BST: 490->500
16. Golem: +20, BST: 495->515
17. Beheeyem :+20, BST: 485->505
18. Spiritomb: +30, BST: 485->515

Edit (8.10.2017):

Potentially replaced TMs

1. Venoshock: Replaced by a Sleep inducing move?
2. Smack Down: Replaced by a Special Rock move?
3. Charge Beam: Replaced by a Special Dragon move?
4. Sludge Wave: Replaced by a Confusion inducing move?
5. Aerial Ace: Replaced by a Special Flying move?
6. Charge Beam: Replaced by a stat increasing move?
7. Sky Drop: Replaced by a Physical Fairy move?
8. Infestation: Replaced by another Special Bug move?
9. Dream Eater: Replaced by a Fairy status?

Potential additional berries:

1. 80 BP Fairy
2. 90 BP Fairy
3. 100 BP Fairy
4. 100 BP Steel
5. 80 BP Normal
6. 90 BP Normal
7. 100 BP Normal

Edit (16.10.2017): There might be another entry hazard. So far we have Rock, Poison, Bug and Ground. The next hazard can be Ice, Flying or Ghost. V-create might also end up having its own tutor.

Edit (09.11.2017): With USUM leaks, the general consensus seems to be something like this:

-Ice/Fairy Physical Attacker Mythical I representing Mineral Ice-types.
-Dark/Ghost pseudo-Pixie Mythical II that might get a form change.
-Ice/Fire cat with Flash Fire to match Volcanion.

Edit(17.11.2017): Potential Move Tutors are:

Gen IV Moves:

1. Dive
2. Pluck
3. Bullet Seed
4. Secret Power
5. Brine
6. Endure
7. Silver Wind
8. Avalanche
9. Captivate
10. Natural Gift
11. Whirlpool
12. Air Cutter
13. Fury Cutter
14. Ominous Wind
15. Sucker Punch
16. Vacuum Wave
17. Swift
18. Mud-slap
19. Rollout
20. Twister
21. String Shot
22. Headbutt
23. Ancient Power

Edit (23.11.2017):

Egg Move Speculation:

1. Patrat: Headbutt
2. Bidoof: Soak
3. Scatterbug: Encore
4. Burmy: N/A
5. Pidove: Brave Bird
6. Pichu: Play Rough
7. Togedemaru: Ion Deluge
8. Sunkern: Encore
9. Purrloin: Tearful Look
10. Meowth: Crunch
11. Carvanha: Soak
12. Krabby: Night Slash
13. Drowzee: Cosmic Power
14. Buneary: Play Rough
15. Diglett: Hone Claws
16. Stunky: Throat Chop
17. Glameow: Pay Day
18. Makuhita: Sky Uppercut
19. Timburr: Counter
20. Munna: Cosmic Power
21. Venonat: Acid Spray
22. Natu: Brave Bird, Charm
23. Abra: Cosmic Power
24. Cottonee: Play Rough
25. Growlithe: Play Rough, Psychic Fangs
26. Buizel: Power-Up Punch
27. Bonsly: Wide Guard
28. Mime Jr.: Cosmic Power
29. Spiritomb: Phantom Force
30. Aipom: Bullet Seed, Rock Blast
31. Durant: Sucker Punch
32. Heatmor: Night Slash
33. Seel: Freeze-Dry, Play Rough
34. Shellder: Barrier
35. Seedot: Magical Leaf, Teeter Dance, Solar Blade
36. Lotad: Dive, Night Slash, Soak
37. Bouffalant: Head Smash
38. Wimpod: Water Shuriken,
39. Sigilyph: Moonblast
40. Swirlix: Natural Gift
41. Spritzee: Present
42. Petilil: Grassy Terrain
43. Karrablast: Lunge
44. Shelmet: Water Sport
45. Cutiefly: Charm
46. Gible: Heavy Slam
47. Lickitung: Heavy Slam
48. Tauros: N/A
49. Miltank: Head Smash
50. Zangoose: Spark,
51. Seviper: Hypnosis
52. Salandit: Dragon Breath
53. Koffing: Lava Plume
54. Skorupi: First Impression,
55. Tangela: Nasty Plot, Night Slash
56. Bounsweet: Sleep Powder
57. Geodude: Head Smash
58. Nosepass: Head Smash
59. Roggenrola: Head Smash, Defense Curl,
60. Rockruff: Head Smash, Rollout
61. Hippopotas: Shore Up, Psychic Fangs
62. Mudbray: Jump Kick
63. Numel: Slack Off
64. Golett: N/A
65. Omanyte: Curse
66. Kabuto: Curse
67. Gothita: Cosmic Power, Moonblast
68. Solosis: Cosmic Power, Hex
69. Zorua: Moonblast, Play Rough, Stored Power, Power Trip
70. Riolu: Mirror Shot, Play Rough, Psychic Fangs, Encore
71. Togepi: Brave Bird
72. Flabébé: Stored Power
73. Elgyem: Wake-Up Slap, Laser Focus
74. Klink: Toxic Spikes
75. Magnemite: N/A
76. Teddiursa: Sweet Scent, Parting Shot
77. Tynamo: N/A
78. Frillish: Reflect Type
79. Tentacool: Aqua Jet
80. Clamperl: Guard Split
81. Mantyke: Hurricane
82. Larvesta: Powder
83. Darumaka: Stored Power, Power Trip, Psychic Fangs
84. Magby: Nasty Plot
85. Elekid: Barrier
86. Blitzle: High Horsepower, 
87. Joltik: Draining Kiss
88. Spheal: Play Rough, Slack Off
89. Swinub: Play Rough, Slack Off
90. Zubat: Final Gambit
91. Minior: N/A
92. Aerodactyl: Psychic Fangs
93. Doduo: Charm
94. Voltorb: N/A.
95. Pancham: Play Rough
96. Stufful: Cotton Guard
97. Taillow: Drill Peck
98. Skarmory: Bone Rush
99. Jangmo-o: Heavy Slam
100. Kecleon: Power Trip, Fire Lash
101. Stantler: Psychic Terrain
102. Girafarig: Stored Power
103. Shroomish: Acid Spray
104. Foongus: Moonlight
105. Slowpoke: Stored Power
106. Psyduck: Stored Power, Reflect Type
107. Staryu: N/A
108. Vanillite: Crafty Shield
109. Cubchoo: Parting Shot
110. Snorunt: Moonblast
111. Snover: Circle Throw
112. Duskull: Phantom Force
113. Litwick: Lava Plume
114. Mismagius: Inferno
115. Honedge: Rollout
116. Ferroseed: Mirror Shot
117. Pawniard: Guard Split
118. Bronzor: N/A
119. Baltoy: N/A
120. Lunatone: N/A
121. Solrock: N/A
122. Ekans: Dragon Dance
123. Grimer: Counter
124. Gulpin: Bullet Seed
125. Trubbish: Metal Sound
126. Gligar: Gust
127. Sneasel: Dual Chop
128. Yanma: Sucker Punch
129. Kangaskhan: Hone Claws
130. Feebas: Liquidation
131. Magikarp: N/A
132. Munchlax: Circle Throw
133. Porygon: N/A
134. Pyukumuku: Memento
135. Lapras: Liquidation
136. Budew: Moonblast
137. Chatot: Hurricane
138. Amaura: Whirlwind
139. Tyrunt: Psychic Fangs
140. Mienfoo: Meteor Mash
141. Phanpy: Stomping Tantrum
142. Onix: Head Smash
143. Pidgey: Boomburst
144. Hoothoot: Charm
145. Oranguru: Moonblast
146. Passimian: Play Rough
147. Cleffa: Nasty Plot
148. Absol: Final Gambit
149. Igglybuff: Wake-Up Slap
150. Skrelp: Dragon Breath
151. Clauncher: Aurora Beam
152. Druddigon: Whirlwind
153. Drampa: Boomburst
154. Turtonator: Inferno
155. Dratini: Tail Slap
156. Noibat: Moonblast
157. Goomy: Belch
158. Deino: Boomburst

Edit: DPPT Remake Move Addition:

1. Turtwig: Leafage, Stomping Tantrum
2. Chimchar: Burn Up, Quick Guard
3. Piplup: Aurora Beam, Night Slash
4. Starly: Pursuit, Punishment
5. Bidoof: Counter, Ice Fang
6. Kricketune: Teeter Dance
7. Shinx: Psychic Fangs, Charm
8. Kadabra: Extrasensory, Gravity
9. Gyarados: Dragon Breath, Feint Attack
10. Roselia: Vine Whip, Acid Spray
11. Zubat: Hurricane, Boomburst
12. Geodude: Mach Punch, Mega Punch
13. Onix: Coil, Shore Up
14. Cranidos: Accelerock, Focus Energy
15. Shieldon: Counter, Noble Roar
16. Machop: Throat Chop, Mach Punch
17. Psyduck: Psycho Shift, Aurora Beam
18. Wormadam/Mothim: Reflect Type
19. Beautifly/Dustox: Stored Power
20. Vespiquen: Punishment, Counter
21. Pachirisu: Electric Terrain, Entrainment
22. Buizel: Liquidation, Parting Shot
23. Cherubi: Play Rough, Charm
24. Shellos: Mud Sport, Water Sport
25. Heracross: Lunge, Dynamic Punch
26. Aipom: Arm Thrust, Play Rough
27. Drifloon: Nasty Plot, Hurricane
28. Buneary: Meditate, Thrash
29. Gastly: Stored Power, Miracle Eye
30. Misdreavus: Miracle Eye, Charm
31. Murkrow: Night Daze, Air Slash
32. Glameow: Tail Slap, Cotton Guard
33. Goldeen: Spike Cannon, Muddy Water
34. Barboach: Double-Edge, Liquidation
35. Chimecho: Hex, Encore
36. Stunky: Inferno, Punishment
37. Meditite: Mach Punch, Psychic Terrain
38. Bronzor: Punishment, Stored Power
39. Ponyta: Burn Up, Jump Kick
40. Sudowoodo: Camouflage, Reflect Type
41. Mr. Mime: Hex, Sweet Kiss
42. Chansey: Play Rough, Perish Song
43. Clefairy: Comet Punch, Teeter Dance
44. Chatot: Ominous Wind, Punishment
45. Pikachu: Ion Deluge, Endeavor
46. Hoothoot: Nasty Plot, Miracle Eye
47. Spiritomb: Inferno, Zap Cannon
48. Gible: Dragon Dance, Night Slash
49. Snorlax: Play Rough, Pound
50. Unown: N/A
51. Lucario: Arm Thrust, Mat Block
52. Wooper: Clear Smog, Camouflage
53. Wingull: Icy Wind, Ominous Wind
54. Girafarig: Play Rough, Stomping Tantrum
55. Hippopotas: Counter, Rock Throw
56. Marill: Sweet Kiss, Belch
57. Skorupi: Punishment, Spikes
58. Croagunk: Mach Punch, Dynamic Punch
59. Carnivine: Psychic Fangs, Leaf Blade
60. Octillery: Rock Wrecker, Head Smash
61. Finneon: Camouflage, Reflect Type
62. Tentacool: Power Gem, Recover
63. Milotic: Moonblast, Aurora Beam
64. Mantine: Bubble Beam, Air Cutter
65. Snover: Ice Hammer, Double-Edge
66. Sneasel: Fury Cutter, Ice Fang
67. Uxie/Mesprit/Azelf: Stored Power
68. Dialga, Palkia, Giratina: Dragon Dance
69. Manaphy: Crafty Shield
70. Rotom: Reflect Type
71. Gligar/Gliscor: Throat Chop, Spikes
72. Nosepass: Ion Deluge, Electric Terrain
73. Ralts: Extrasensory, Telekinesis
74. Lickitung: Punishment, Camouflage
75. Eevee: Power Trip, Sweet Kiss
76. Swablu: Brave Bird, Double-Edge
77. Togepi: Moonblast, Hyper Voice
78. Houndour: Power Trip, Lava Plume
79. Magnemite: Ion Deluge, Eerie Impulse
80. Tangela: Stored Power, Punishment
81. Yanma: Punishment, Final Gambit
82. Tropius: Dragon Breath, Belch
83. Rhyhorn: Night Slash, Head Smash
84. Duskull: Nasty Plot, Inferno
85. Porygon: Zap Cannon, Ion Deluge
86. Scyther: Psycho Cut, Sacred Sword
87. Elekid: Mach Punch, Ion Deluge
88. Magby: Inferno, Dynamic Punch
89. Swinub: Stomping Tantrum, Counter
90. Snorunt: Icicle Smash, Phantom Force
91. Absol: Night Daze, Confuse Ray
92. Cresselia: Draining Kiss
93. Darkrai: Phantom Force, Confuse Ray
94. Heatran: Recover, Mirror Shot
95. Regigigas: Ice Hammer, Meteor Mash
96. Phione: Liquidation, Play Rough
97. Shaymin: Moonblast, Defense Curl

Edit (04.02.2018):

Moves to be updated

1. Smog
2. Aromatic Mist
3. Twineedle
4. Payback
5. Dragon Rush
6. Slam
7. Charge Beam
8. Razor Leaf
9. Sweet Kiss
10. Mud-Slap
11. Lick

Edit (06.02.2018):

Moveset wishlist update:

1. Patrat: Double-Edge
2. Bidoof: Bite
3. Vivillon: Signal Beam
4. Mothim: Air Cutter
5. Wormadam: Signal Beam
6. Pidove: Brave Bird
7. Pikachu: Ion Deluge
8. Pachirisu: Nasty Plot
9. Togedemaru: Iron Defense
10. Sunkern: Earth Power
11. Purrloin: Encore
12. Meowth: Uproar
13. Carvanha: Fury Cutter
14. Krabby: Fury Cutter
15. Drowzee: Psywave
16. Buneary: Headbutt
17. Diglett: Fury Cutter
18. Stunky: Poison Fang
19. Glameow: Parting Shot
20. Makuhita: Power-Up Punch
21. Timburr: Headbutt
22. Munna: Flash
23. Venonat: Flash
24. Natu: Air Cutter, Extrasensory
25. Kadabra: Signal Beam
26. Cottonee: Flash
27. Growlithe: Revenge
28. Buizel: Dive
29. Bonsly: Rock Blast
30. Mime Jr.: Psywave
31. Spiritomb: Phantom Force
32. Aipom: Rock Blast
33. Durant: Struggle Bug
34. Heatmor: Slash
35. Seel: Whirlpool
36. Shellder: Pin Missile
37. Seedot: Seed Bomb
38. Lotad: Aqua Jet
39. Bouffalant: Iron Head
40. Wimpod: Iron Defense
41. Woobat: Giga Drain
42. Sigilyph: Gust
43. Swirlix: Baby-Doll Eyes
44. Spritzee: Gust
45. Petilil: Grassy Terrain
46. Karrablast: Sucker Punch
47. Shelmet: Sludge
48. Cutiefly: Play Rough
49. Gible: Bite
50. Regis: Laser Focus
51. Lickitung: Hammer Arm
52. Tauros: Megahorn
53. Miltank: Megahorn
54. Zangoose: Power-Up Punch
55. Seviper: Fury Cutter
56. Salandit: Aromatic Mist
57. Koffing: Acid
58. Skorupi: Hone Claws
59. Tangela: Seed Bomb
60. Bounsweet: Growth
61. Geodude: Mud-Slap
62. Nosepass: Ancient Power
63. Rockruff: Play Rough
64. Hippopotas: Mud-Slap
65. Mudbray: Iron Head
66. Numel: Stomping Tantrum
67. Golett: Mud-Slap
68. Omanyte: Liquidation
69. Kabuto: Liquidation
70. Gothita: Role Play
71. Solosis: Role Play
72. Zorua: Hone Claws
73. Riolu: Wake-Up Slap
74. Togepi: Dizzy Punch
75. Flabébé: Extrasensory
76. Elgyem: Laser Focus
77. Klink: Skill Swap
78. Magnemite: Skill Swap
79. Teddiursa: Arm Thrust
80. Eelektrik: Poison Fang
81. Frillish: Draining Kiss
82. Tentacool: Knock Off
83. Huntail/Gorebyss: Liquidation
84. Mantyke: Psywave
85. Larvesta: Inferno
86. Darumaka: Arm Thrust
87. Magby: Headbutt
88. Elekid: Headbutt
89. Blitzle: High Horsepower
90. Joltik: Pin Missile
91. Spheal: Liquidation
92. Swinub: Stomping Tantrum
93. Zubat: Brave Bird
94. Minor: Acrobatics
95. Aerodactyl: Crush Claw
96. Hawlucha: Power-Up Punch
97. Doduo: Stomping Tantrum
98. Voltorb: Zap Cannon, Tri Attack
99. Pancham: Iron Head
100. Stufful: Comet Punch
101. Taillow: Air Cutter
102. Skarmory: Crush Claw
103. Jangmo-o: Hyper Voice
104. Regigigas: Rest
105. Latias/Latios: Ally Switch
106. Kecleon: Ally Switch
107. Stantler: Scary Face
108. Girafarig: Miracle Eye
109. Shroomish: Seed Bomb
110. Foongus: Seed Bomb
111. Slowpoke: Extrasensory
112. Psyduck: Skill Swap
113. Staryu: Skill Swap
114. Vanillite: Haze
115. Cubchoo: Mist
116. Snorunt: Mist
117. Snover: Grassy Terrain
118. Duskull: Nightmare
119. Litwick: Nightmare
120. Misdreavus: Nightmare
121. Drifloon: Nightmare
122. Honedge: Lunge
123. Ferroseed: Grassy Terrain
124. Pawniard: Throat Chop
125. Bronzor: Heal Pulse
126. Baltoy: Heal Pulse
127. Lunatone: Heal Pulse
128. Solrock: Heal Pulse
129. Ekans: Dragon Rush
130. Grimer: Destiny Bond
131. Gulpin: Destiny Bond
132. Trubbish: Encore
133. Gligar: Lunge
134. Sneasel: Power-Up Punch
135. Yanma: Air Cutter
136. Kangaskhan: Mach Punch
137. Milotic: Dragon Dance
138. Gyarados: Coil
139. Munchlax: Super Fang
140. Porygon: Eerie Impulse
141. Pyukumuku: Gastro Acid
142. Lapras: Curse
143. Budew: Vine Whip
144. Chatot: Twister
145. Amaura: Charm
146. Tyrunt: Accelerock
147. Mienfoo: Heal Pulse
148. Phanpy: Stomping Tantrum
149. Onix: Ancient Power
150. Pidgey: Ominous Wind
151. Hoothoot: Twister
152. Oranguru: Encore
153. Passimian: Encore
154. Clefairy: Comet Punch
155. Absol: Miracle Eye
156. Jigglypuff: Self-Destruct
157. Skrelp: Clear Smog
158. Clauncher: Clear Smog
159. Drampa: Air Cutter
160. Turtonator: Iron Defense
161. Dratini: Coil
162. Noibat: Dragon Rush
163. Goomy: Sludge
164. Deino: Nasty Plot

Edit(11.04.2018):

Ability buffs:

1. Run Away: Should be updated to Ghost's immunity to trapping.
2. Damp: Should have Water Sport's effect add-on.
3. Early Bird: Should have additional effect.
4. Blaze/Overcoat/Torrent/Swarm: Should start effect at half health.

Edit(17.04.2018):

1. Grass Starter Signature Move: 85 BP, Special , %100 Accuracy
2. Fire Starter Signature Move: 90 BP, Physical, %100 Accuracy.
3. Water Starter Signature Move: 70 BP, Physical, %100 Accuracy.

Edit(02.05.2018):

Looking at my older posts, apparently this generation will make Water 1 reach around 100+, this means Water 1 Egg Group will have a generation's worth of Pokémon. This also means Water Egg Group can be partitioned for a fourth time, this one likely focusing on amphibians, combining stuff from Human-Like and Field(Croagunk and Wooper respectively). While Water 1 still needs a Ghost and Fire to be complete, and will likely only get another Water/Grass, and some other secondary Water typings(Ground/Water, Psychic/Water, Fighting/Water etc.).

Edit (05.05.2018):
With the Pokédex speculation we have, Field/Amorphous is a likely Egg Group. That will help Poison and lesser extent Ghost.

Edit (04.06.2018): Looking at my speculations:

Speculation 1

Unique type combinations

1. Grass/Rock
2. Water/Ghost-Ghost/Water
3. Grass/Water
4. Fire/Electric
5. Fighting/Rock
6. Dark/Normal
7. Water/Steel
8. Steel/Fire
9. Electric/Normal or Electric/Ground
10. Rock/Fire
11. Psychic/Ground
12. Poison/Fighting
13. Fairy/Dragon
14. Flying
15. Psychic/Electric
16. Ice/Fairy

Unused type combinations:

1. Fire/Fairy
2. Normal/Electric
3. Electric/Fighting
4. Rock/Ghost
5. Ice/Normal
6. Dragon/Bug
7. Steel/Normal

Speculation 2

Unique type combinations

1. Fire/Poison
2. Fairy/Flying
3. Grass/Ground
4. Dark/Ground
5. Fighting/Rock
6. Normal/Electric
7. Psychic/Ice
8. Ice/Fighting
9. Ice/Rock
10. Grass/Rock
11. Rock/Dark
12. Bug/Fairy
13. Dragon/Steel
14. Dragon/Normal

Unused type combinations:

1. Fairy/Fire
2. Ice/Normal
3. Fairy/Fighting
4. Rock/Ghost

Update(25.09.2018):

Assuming same amount of species introduced in S/M, ignoring US/UM additions beyond the final count:

Water: 146

Grass: 113

Normal: 111

Flying: 109

Psychic: 95

Bug: 88

Fire: 76

Poison: 71

Ground: 69

Fighting: 67

Rock: 64

Fairy: 63

Dark: 62

Electric: 61

Steel: 61

Ghost: 54

Dragon: 53

Ice: 45

Outside of the Fairies this is highly unlikely, but it gives an image of what to expect.

Update(20.01.2019):
With USUM count:
Water: 120->133->146
Normal: 97->109->121
Flying: 93->101->109
Grass: 85->98->111
Psychic: 75->86->97
Bug: 66->77->88
Fire: 59->68->76
Poison: 59->66->73
Ground: 61->65->69
Rock: 55->60->65
Fighting: 47->57
Dark:46->54->62
Steel: 42->54->66
Electric: 42->52->62
Fairy: 37->50->63
Dragon: 41->50->59
Ghost: 35->45->55
Ice: 35->40->45

If a type were to be introduced now:

1. Main objective of a new type should be buffing Ice-type defensively. Most offensive types are perfectly balanced, with the possible exception of Ground. However, Ice is one of the most irrelevant and worst types, and it needs significant boost.
2. Buffing Electric-type should be considered for offense, as Electric needs one more super-effectiveness to become balanced and match Flying/Grass/Water.
3. Rebuffing Dragon, Dark, Poison and Psychic can be considered. Dark and Poison need one more offensive option, Psychic needs an offensive and defensive option, and Dragon needs something else besides itself to hit.
4. Grass and Bug are just bad in general, and Rock would enjoy one more resistance to become balanced, or more ideally lose a weakness.

Edit(31.01.2019): Cleaned up the post with USUM additions.

Edit(11.02.2019):
Possible mid-game introductions include:

Gen VI Remakes:

1. Ponyta pre-evo.
2. Goldeen pre-evo.
3. Buneary pre-evo.
4. Croagunk pre-evo.
5. Onix pre-evo.
6. Carnivine pre-evo.
7. Heatran pre-evo.

Gen II LG games:

1. Dragon/Electric Legendary
2. Dragon/Grass sub-legendary
3. Dragon/Fire sub-legendary
4. Dragon/Water sub-legendary

DPPt moveset notes:

***First stage is above Level 50.

Original 151:

1. Turtwig: Turtwig's moveset caps at Level 45.
2. Chimchar: Chimchar's moveset caps at Level 47.
3. Piplup: Piplup's moveset caps at Level 43.
4. Starly: Starly's moveset caps at Level 41.
5. Bidoof: Bidoof's moveset caps at Level 49.
6. Kricketot: Kricketot's moveset caps at Level 16. Kricketune's moveset caps at Level 50.
7. Shinx: Shinx's moveset caps at Level 45.
8. Abra: Abra's moveset caps at Start. Kadabra's moveset caps at Level 46.
9. Magikarp: Magikarp's moveset caps at Level 30. Gyarados' moveset caps at Level 54.
10. Budew: Budew's moveset caps at Level 16. Roselia's moveset caps at Level 50.
11. Zubat: Zubat's moveset caps at Level 43.
12. Geodude: Geodude's moveset caps at Level 42.
13. Onix: Onix's moveset caps at Level 52.***
14. Cranidos: Cranidos' moveset caps at Level 46.
15. Shieldon: Shieldon's moveset caps at Level 46.
16. Machop: Machop's moveset caps at Level 45.
17. Psyduck. Psyduck's moveset caps at Level 43.
18. Burmy: Burmy's moveset caps at Level 20. Wormadam's and Mothim's movesets cap at Level 50.
19. Wurmple: Wurmple's moveset caps at Level 15. Beautifly's and Dustox's movesets cap at Level 40.
20. Combee: Combee's moveset caps at Level 29. Vespiquen's moveset caps at Level 57.
21. Pachirisu: Pachirisu's moveset caps at Level 49.
22. Buizel: Buizel's moveset caps at Level 45.
23. Cherubi: Cherubi's moveset caps at Level 47.
24. Shellos: Shellos' moveset caps at Level 46.
25. Heracross: Heracross' moveset caps at Level 46.
26. Aipom: Aipom's moveset caps at Level 43.
27. Drifloon: Drifloon's moveset caps at Level 50.
28. Buneary: Buneary's moveset caps at Level 63.***
29. Gastly: Gastly's moveset caps at Level 47.
30. Misdreavus: Misdreavus' moveset caps at Level 55.***
31. Murkrow: Murkrow's moveset caps at Level 65.***
32. Glameow: Glameow's moveset caps at Level 50.
33. Goldeen: Goldeen's moveset caps at Level 45.
34. Barboach: Barboach's moveset caps at Level 44.
35. Chimecho. Chingling's moveset caps at Level 32. Chimecho's moveset caps at Level 57.
36. Stunky: Stunky's moveset caps at Level 45.
37. Meditate: Meditate's moveset caps at Level 44.
38. Bronzor: Bronzor's moveset caps at Level 49.
39. Ponyta: Ponyta's moveset caps at Level 49.
40. Sudowoodo: Bonsly's moveset caps at Level 43. Sudowoodo's moveset caps at Level 54.
41. Mr. Mime: Mime Jr. and Mr. Mime's moveset cap at Level 50.
42. Chansey: Happiny's moveset caps at Level 12. Chansey's moveset caps at Level 65.
43. Clefairy: Cleffa's moveset caps at Level 16. Clefairy's moveset caps at Level 58.
44. Chatot: Chatot's moveset caps at Level 57.***
45. Pikachu: Pichu's moveset caps at Level 18. Pikachu's moveset caps at Level 58.
46. Hoothoot: Hoothoot's moveset caps at Level 46.
47. Spiritomb: Spiritomb's moveset caps at Level 49.
48. Gible: Gible's moveset caps at Level 37.
49. Munchlax: Munchlax's moveset caps at Level 57. Snorlax's moveset caps at Level 57.***
50. Unown: N/A
51. Riolu: Riolu's moveset caps at Level 50. Lucario's moveset caps at Level 65.
52. Wooper: Wooper's moveset caps at Level 47.
53. Wingull: Wingull's moveset caps at Level 43.
54. Girafarig: Girafarig's moveset caps at Level 50.
55. Hippopotas: Hippopotas' moveset caps at Level 50.
56. Azurill: Azurill's moveset caps at Level 23. Marill's moveset caps at Level 47.
57. Skorupi: Skorupi's moveset caps at Level 49.
58. Croagunk: Croagunk's moveset caps at Level 50.
59. Carnivine: Carnivine's moveset caps at Level 50.
60. Remoraid: Remoraid's moveset caps at Level 50.
61. Finneon: Finneon's moveset caps at Level 54.***
62. Tentacool: Tentacool's moveset caps at Level 49.
63. Feebas: Feebas' moveset caps at Level 30. Milotic's moveset caps at Level 47.
64. Mantine: Mantyke's and Mantine's movesets cap at Level 49.
65. Snover: Snover's moveset caps at Level 46.
66. Sneasel: Sneasel's moveset caps at Level 47.
67. Uxie: Uxie's moveset caps at Level 76.***
68. Mesprit: Mesprit's moveset caps at Level 76.***
69. Azelf: Azelf's moveset caps at Level 76.***
70. Dialga: Dialga's moveset caps at Level 50.
71. Palkia: Palkia's moveset caps at Level 50.
72. Manaphy: Manaphy's moveset caps at Level 76.***

Platinum additions:

1. Rotom: Rotom's moveset caps at Level 64.***
2. Gligar: Gligar's moveset caps at Level 55. ***
3. Nosepass: Nosepass' moveset caps at Level 43.
4. Ralts: Ralts' moveset caps at Level 42.
5. Lickitung: Lickitung's moveset caps at Level 57.***
6. Eevee: Eevee's moveset caps at Level 45.
7. Swablu: Swablu's moveset caps at Level 46.
8. Togepi: Togepi's moveset caps at Level 53.***
9. Houndour: Houndour's moveset caps at Level 56.***
10. Magnemite: Magnemite's moveset caps at Level 49.
11. Tangela: Tangela's moveset caps at Level 50.
12. Yanma: Yanma's moveset caps at Level 57.***
13. Tropius: Tropius' moveset caps at Level 61.***
14. Rhyhorn: Rhyhorn's moveset caps at Level 53.***
15. Duskull: Duskull's moveset caps at Level 54.***
16. Porygon: Porygon's moveset caps at Level 62.***
17. Scyther: Scyther's moveset caps at Level 61.***
18. Elekid: Elekid's moveset caps at Level 43.
19. Magby: Magby's moveset caps at Level 43.
20. Swinub: Swinub's moveset caps at Level 48.
21. Snorunt: Snorunt's moveset caps at Level 50.
22. Absol: Absol's moveset caps at Level 57.***
23. Giratina: Giratina's moveset caps at Level 50.

Others:

1. Heatran: Heatran's moveset caps at Level 96.***
2. Regigigas: Regigigas' moveset caps at Level 100. ***
3. Cresselia: Cresselia's moveset caps at Level 99.***
4. Phione: Phione's moveset caps at Level 69.***
5. Darkrai: Darkrai's moveset caps at Level 93.***
6. Shaymin: Shaymin's moveset caps at Level 100.***
7. Arceus: Arceus' moveset caps at Level 100.***

Dex speculation moveset notes:

1. Patrat.: Patrat's moveset caps at Level 41.
2. Bidoof: See above
3. Scatterbug: Scatterbug's moveset caps at Level 15. Vivillon's moveset caps at Level 55.
4. Burmy: See above
5. Pidove: Pidove's moveset caps at Level 50.
6. Pichu: See above.
7. Pachirisu: See above.
8. Togedemaru: Togedemaru's moveset caps at Level 53.***
9. Sunkern: Sunkern's moveset caps at Level 43.
10. Purrloin: Purrloin's moveset caps at Level 49.
11. Meowth: Regular Form's moveset caps at Level 50. Alolan Form's moveset caps at Level 55.***
12. Carvanha: Carvanha's moveset caps at Level 43.
13. Krabby: Krabby's moveset caps at Level 45.
14. Drowzee: Drowzee's moveset caps at Level 61.***
15. Buneary: See above.
16. Diglett: Both forms' movesets cap at Level 43.
17. Stunky: See above.
18. Glameow: See above.
19. Makuhita: Makuhita's moveset caps at Level 46.
20. Timburr: Timburr's moveset caps at Level 49.
21. Munna: Munna's moveset caps at Level 47.
22. Venonat: Venonat's moveset caps at Level 47.
23. Natu: Natu's moveset caps at Level 50.
24. Abra: See above.
25. Cottonee: Cottonee's moveset caps at Level 46.
26. Growlithe: Growlithe's moveset caps at Level 45.
27. Buizel: See above.
28. Bonsly: See above.
29. Mime Jr.: See above.
30. Spiritomb: See above.
31. Aipom: See above.
32. Durant: Durant's moveset caps at Level 56.***
33. Heatmor: Heatmor's moveset caps at Level 66.***
34. Seel: Seel's moveset caps at Level 53.***
35. Shellder: Shellder's moveset caps at Level 61.***
36. Seedot: Seedot's moveset caps at Level 33.
37. Lotad: Lotad's moveset caps at Level 36.
38. Bouffalant: Bouffalant's moveset caps at Level 61.***
39. Wimpod: Wimpod's moveset caps at start. Golisopod's moveset caps at Level 48.
40. Woobat: Woobat's moveset caps at Level 47.
41. Sigilyph: Sigilyph's moveset caps at Level 50.
42. Swirlix: Swirlix's moveset caps at Level 67.***
43. Spritzee: Spritzee's moveset caps at Level 50.
44. Petilil: Petilil's moveset caps at Level 46.
45. Karrablast: Karrablast's moveset caps at Level 56.***
46. Shelmet: Shelmet's moveset caps at Level 56.***
47. Cutiefly: Cutiefly's moveset caps at Level 41.
48. Gible: See above.
49. Regirock: Regirock's moveset caps at Level 67.***
50. Regice: Regice's moveset caps at Level 67.***
51. Registeel: Registeel's moveset caps at Level 67.***
52. Lickitung: See above.
53. Tauros: Tauros' moveset caps at Level 71.***
54. Miltank: Miltank's moveset caps at Level 50.
55. Zangoose: Zangoose's moveset caps at Level 50.
56. Seviper: Seviper's moveset caps at Level 46.
57. Salandit: Salandit's moveset caps at Level 48.
58. Koffing: Koffing's moveset caps at Level 45.
59. Skorupi: See above.
60. Tangela: See above.
61. Bounsweet: Bounsweet's moveset caps at Level 33.
62. Geodude: See above.
63. Nosepass: See above.
64. Roggenrola: Roggenrola's moveset caps at Level 40.
65. Rockruff: Rockruff's moveset caps at Level 48.
66. Hippowdon: See above.
67. Mudbray: Mudbray's moveset caps at Level 45.
68. Numel: Numel's moveset caps at Level 47.
69. Golett: Golett's moveset caps at Level 61.***
70. Omanyte: Omanyte's moveset caps at Level 55.***
71. Kabuto: Kabuto's moveset caps at Level 50.
72. Gothita: Gothita's moveset caps at Level 48.
73. Solosis: Solosis' moveset caps at Level 48.
74. Zorua: Zorua's moveset caps at Level 57.***
75. Riolu: See above.
76. Togepi: See above.
77. Flabébé: Flabébé's moveset caps at Level 48.
78. Elgyem: Elgyem's moveset caps at Level 56.***
79. Klefki: Klefki's moveset caps at Level 50.
80. Klink: Klink's moveset caps at Level 57.***
81. Magnemite: See above.
82. Teddiursa: Teddiursa's moveset caps at Level 57.***
83. Tynamo: Tynamo's moveset caps at Start. Eelektrik's moveset caps at Level 74.
84. Frillish: Frillish's moveset caps at Level 61.***
85. Tentacool: See above.
86. Clamperl: Clamperl's moveset caps at Level 50. Huntail and Gorebyss' movesets cap at Level 50.
87. Mantyke: See above.
88. Larvesta: Larvesta's moveset caps at Level 100.
89. Darumaka: Darumaka's moveset caps at Level 52.
90. Magby: See above.
91. Elekid: See above.
92. Blitzle: Blitzle's moveset caps at Level 43.
93. Joltik: Joltik's moveset caps at Level 48.
94. Spheal: Spheal's moveset caps at Level 46.
95. Swinub: See above.
96. Zubat: See above.
97. Minior: Minior's moveset caps at Level 50.
98. Aerodactyl: Aerodactyl's moveset caps at Level 81.***
99. Hawlucha: Hawlucha's moveset caps at Level 60.***
100. Doduo: Doduo's moveset caps at Level 50.
101. Voltorb: Voltorb's moveset caps at Level 48.
102. Pancham: Pancham's moveset caps at Level 48.
103. Stufful: Stufful's moveset caps at Level 50.
104. Taillow: Taillow's moveset caps at Level 45.
105. Skarmory: Skarmory's moveset caps at Level 53.***
106. Jangmo-o: Jangmo-o's moveset caps at Level 53.***
107. Regigigas: See above.
108. Latias: Latias' moveset caps at Level 61.***
109. Latios: Latios' moveset caps at Level 61.***
110. Kecleon: Kecleon's moveset caps at Level 50.
111. Stantler: Stantler's moveset caps at Level 55.***
112. Girafarig: See above.
113. Shroomish: Shroomish's moveset caps at Level 40.
114. Foongus: Foongus' moveset caps at Level 50.
115. Slowpoke: Slowpoke's moveset caps at Level 58.***
116. Psyduck: See above.
117. Staryu: Staryu's moveset caps at Level 53.***
118. Vanillite: Vanillite's moveset caps at Level 53.***
119. Cubchoo: Cubchoo's moveset caps at Level 57.***
120. Snorunt: See above.
121. Snover: See above.
122. Duskull: See above.
123. Litwick: Litwick's moveset caps at Level 61.***
124. Misdreavus: See above.
125. Drifloon: See above.
126. Honedge: Honedge's moveset caps at Level 47.
127. Ferroseed: Ferroseed's moveset caps at Level 55.***
128. Pawniard: Pawniard's moveset caps at Level 62.***
129. Bronzor: See above.
130. Baltoy: Baltoy's moveset caps at Level 46.
131. Lunatone: Lunatone's moveset caps at Level 49.
132. Solrock: Solrock's moveset caps at Level 49.
133. Ekans: Ekans' moveset caps at Level 49.
134. Grimer: Both forms' movesets cap at Level 48.
135. Gulpin: Gulpin's moveset caps at Level 49.
136. Trubbish: Trubbish's moveset caps at Level 47.
137. Gligar: See above.
138. Sneasel: See above.
139. Yanma: See above.
140. Kangaskhan: Kangaskhan's moveset caps at Level 50.
141. Feebas: See above.
142. Magikarp: See above.
143. Munchlax: See above.
144. Porygon: See above.
145. Pyukumuku: Pyukumuku's moveset caps at Level 49.
146. Lapras: Lapras' moveset caps at Level 50.
147. Budew: See above.
148. Chatot: See above.
149. Amaura: Amaura's moveset caps at Level 65.***
150. Tyrunt: Tyrunt's moveset caps at Level 49.
151. Mienfoo: Mienfoo's moveset caps at Level 61.***
152. Phanpy: Phanpy's moveset caps at Level 42.
153. Onix: See above.
154. Pidgey: Pidgey's moveset caps at Level 53.***
155. Hoothoot: See above.
156. Oranguru: Oranguru's moveset caps at Level 50.
157. Passimian: Passimian's moveset caps at Level 50.
158. Cleffa: See above.
159. Absol: See above.
160. Igglybuff: Igglybuff's moveset caps at Level 11. Jigglypuff's moveset caps at Level 45.
161. Skrelp: Skrelp's moveset caps at Level 49.
162. Clauncher: Clauncher's moveset caps at Level 48.
163. Druddigon: Druddigon's moveset caps at Level 62.***
164. Drampa: Drampa's moveset caps at Level 53.***
165. Turtonator: Turtonator's moveset caps at Level 53.***
166. Dratini: Dratini's moveset caps at Level 61.***
167. Noibat: Noibat's moveset caps at Level 58.***
168. Goomy: Goomy's moveset caps at Level 42.
169. Deino: Deino's moveset caps at Level 62.***