GenI
Squirtal, Wartortle, and Blastiose
Charmander, Charmeleon, and Charizard
Bulbasaur, Ivysaur, and Venusaur
GenII
Totodile, Croconaw, and Feraligatr
Cyndaquil, Quilava, and Typholsion
Chikorita, Bayleef, and Meganium
GenIII
Treecko, Grovyle, and Sceptile
Mudkip, Marshtomp, and Swampert...