Species that have not seen major Gym Leader/Elite Four/Villain/NPC representatives:

Bug:

1. Butterfree
2. Beedrill
3. Ledian
4. Ninjask
5. Shedinja
6. Kricketune
7. Wormadam
8. Mothim

Dark:

1. Alolan Raticate

Dragon:

1. N/A

Electric:

1. Plusle 
2. Minun 
3. Pachirisu 
4. Stunfisk

Fairy:

1. Azumarill
2. Audino
3. Whimsicott
4. Florges
5. Aromatisse
6. Slurpuff

Fighting:

1. Pangoro

Fire:

1. Heatmor

Flying:

1. Fearow
2. Farfetch'd
3. Chatot
4. Minior

Ghost:

1. N/A

Grass:

1. Lilligant

Ground:

1. Sandshrew
2. Marowak
3. Donphan
4. Diggersby

Ice:

1. N/A

Normal:

1. Raticate
2. Ditto
3. Furret
4. Blissey
5. Dunsparce
6. Ursaring
7. Stantler
8. Linoone
9. Exploud*
10. Delcatty
11. Zangoose
12. Kecleon
13. Sawsbuck
14. Furfrou*

Poison:

1. Tentacruel
2. Qwilfish
3. Swalot
4. Amoonguss

Psychic:

1. Wobbuffet
2. Grumpig
3. Chimecho

Rock:

1. Corsola

Steel:

1. N/A

Water:

1. Kingler
2. Seaking
3. Huntail
4. Gorebyss
5. Bibarel
6. Lumineon
7. Alomomola
8. Pyukumuku