>Red
Gen 1, the originals, basically just a random game, not much planned for the future, pokemania happened quickly
>orange
Gen 2, a transition, Gamefreak still wasn't completely sure how far this would go, but knew they had a chance to profit (see dev interviews talking about marketability of designs at this time)
>yellow
Gen 3-BW, "New" pokemon, starting with RSE, the formula was locked in for a while. QoL changes were made over time, but the structure of the games and other content stayed mostly the same
>green
BW2-SwSh, "Nu" pokemon, a negative reaction to BW1 led to some changes, mostly the same formula as before, but with an emphasis on appealing to older fans, starting with XY there were fewer new pokemon each gen, but new forms of older pokemon as megas, then regionals
>blue
LA and SV, "post-nu" pokemon, starting with SwSh's DLC, there was a new focus on opening up the world with more drastic formula changes, this may or may not evolve into something else, hard to tell right now
>white
LGPE and BDSP, can't really be called anything, just experimental games that filled space for others
