Notes on average stats for types

-Bug: Bug is statistically the worst type, being the worst in total stats, HP, and quite low in other stats. It's highest rankings come from Speed(12th) and Defense(12th), though fully evolved Bug-types tend to be heavily offense oriented(11th).

-Poison: Poison is the second worst type statistically. Its lowest stats are HP, Attack and Defense. Its best stat in comparison to other types is Speed.

-Normal: Normal is statistically the third worst type(second worst fully evolved), being the worst in Defense, Special Defense and Special Attack. It excels in HP and Speed, however.

-Grass: Grass is the fourth weakest type statistically. Its worst stat is Speed. Its Attack and Defense are its only better stats compared to other types.

-Water: Water is the fifth weakest type. Its stats are generally average, as such it only becomes significant when fully evolved. Fully Evolved Water-types excel at HP, Defense and Sp. Attack.

-Fairy: Fairy is the sixth weakest type, and the weakest type for Attack, and it fails at HP and Speed as well. It is, however, one of the best types for Special Attack and Special Defense.

-Ground: Ground is the seventh weakest type, and excels in HP, Attack, Defense while utterly failing Special Attack, Defense Speed.

-Ghost: Ghost is the eighth weakest type(fourth worst fully evolved), failing in HP and Speed, but excelling in Defense and Special Attack.

-Electric: Electric is the ninth weakest type(sixth worst fully evolved), failing in HP, Attack, Defense, but excelling in Special Attack and Speed.

-Rock: Rock is the tenth weakest type, excelling in Defense, failing in Special Attack, Defense, and being the slowest type in the game.

-Flying: Flying is the eleventh weakest type, failing in Defense and Special Defense, excelling in Speed(being the fastest type overall) and being average in other stats.

-Fire: Fire is the twelfth weakest type(third best type fully evolved), excelling in Special Attack and being average in all stats except Defense, at which it is terrible.

-Dark: Dark is the thirteenth weakest type statistically, excelling in Attack, and failing in Special Attack, Defense, and Special Defense, with average HP and Speed.

-Ice: Ice is the fourteenth weakest type statistically, excelling in HP, being weak in Speed and being average in all other stats.

-Fighting: Fighting is the fourth best type(fifth fully evolved), having the best Attack in the game, with terrible Defense and Special Attack, bad Special Defense, good Speed and HP.

-Psychic: Psychic is the third best type(second fully evolved), second highest Special Attack, average HP, below average Defense, overall best Special Defense, and fourth best Speed, with terrible Attack.

-Steel: Steel is the second best type(fourth best fully evolved), with best Defense, good Attack, terrible HP, Speed and Special Attack, good Special Defense.

-Dragon: Dragon is the best type statistically, being the best in HP and Special Attack and great in all other stats, with its weakest stats being Defense and Speed.

First stage Pokémon according to their BST

Middle stages according to BSTs

notes on stat retcons

So far, two of the recent generations have buffed stats of existing Pokémon.

Gen 6 buffed stats of Pokémon that evolve at third stage by +10, except for Pikachu who got +20. About 29 Pokémon were buffed this way.

Gen 7 buffed stats of Pokémon that evolve at second stage and some single stage Pokémon and Woobat in a range of 10 to 40. HP was also buffed. About 26 Pokémon were buffed this way.

If this continues, assuming 20 buffs for each generation, by Gen 15, all Pokémon introduced since Gen 1 to 7 will have become buffed, in theory anyways(in practice, there will be stuff that remain).

Nonetheless a scenario like this one can be presented:

Gen 8: Buffing single stage Pokémon and some others.
Gen 9: Buffing middle stage Pokémon and some others.
Gen 10: Buffing first stage Pokémon and some others.
Gen 11: Buffing babies and some others.
Gen 12: Buffing weakest ones and some others.
Gen 13: Buffing some mascot legendaries and some others.
Gen 14: Buffing some minor legendaries and some others.
Gen 15: Buffing some Mega Evolving Pokémon and some others.
Gen 16: Buffing some Pokémon that have special gimmicks and others.
Gen 17: Buffing some former fully evolved Pokémon and others.
Gen 19: Return to third stages with higher BST upgrade.
Gen 20: Return to second stages with higher BST upgrade.
Gen 21: Repeat Gen 8 onwards with higher BST upgrade.

Pokémon according to EV spreads

Highest stat-type correlation (Updated for USUM/Let's Go)