first game: Pokémon Black: Snivy
2nd game: White: Tepig
3rd: Grey: Oshawott
I've been choosing them in grass-fire-water since Gen I (yes I'm that old lol) I got Bulbasaur in Blue, Charizard in red..then Chickorita in Gold, cynda in silver, and totodile in crytal..etc..all the way to the gen iv remakes (chickorita hg, cynda ss). I honestly don't remember why I started to do that/chose bulbasaur..but I've kept it up since