There are 44 pokemon from all gens

Gen 1
Arcanine
Articuno
Charizard
Dragonite
Eevee
Gastly
Gengar
Haunter
Lickitung
Mewtwo
Moltres
Rapidash
Scyther
Snorlax
Squirtle
Zapdos

Gen 2
Lugia
Scizor
Suicune
Typhlosion
Tyranitar

Gen 3
Absol
Flygon
Groudon
Primal Groudon
Mightyena
Rayquaza

Gen 4
Arceus
Lucario
Luxray

Gen 5
Reshiram
Samurott
Zekrom

Gen 6
Gardevoir
Mega Charizard X
Talonflame
Xerneas

Gen 7
Alolan Exeggutor
Lycanroc
Mimikyu
Solgaleo


Gen 8
Corviknight
Gigantamax Pikachu

Mixed
Eeveelution (All eevee evolutions)

Notes:
These models have no animations
All models have collision
Might be some texture bugs but nothing too big
I used bulbapedia for the pokemon sizes, they're not all accurate though
These 12 pokemon all have emissive elements (they glow at night):
Articuno
Charizard
Gastly
Mega Charizard X
Moltres
Gigantamax Pikachu
Rapidash
Reshiram
Typhlosion
Xerneas
Zapdos
Zekrom

Credits:

Nintendo
Game Freak
Creatures, Inc.

All models are from www.models-resource.com

Thanks to these users from models-resource.com for providing the models:

Random Talking Bush
Centrixe
Ziella
Hallow
lemurboy12
Pocket Studios
Link101
Lilothestitch
Perseus
Mystie

Install instructions:
Addonprops is required for add-on method

Replace method:
Rename one of the pokemon files to one of the gta v props files (.ydr)

Add-on method:
Install addon props, https://www.gta5-hub.com/tools/addonprops

Next go to mods > update > x64 > dlcpacks > addonprops > dlc > props

Copy everything from the 'main files' folder to the props folder

If this is your first time installing addonprops you can delete everything that's already in the props folder if you want

If you already have addonprops installed and you have custom props, make sure to NOT replace the 'def props.ytyp' file or all your custom props won't spawn in game and you're going to have to manually add all the pokemon

Use menyoo or simple trainer to spawn objects

Enjoy