It's so hard to choose between so many-but seeing as how I'm picky on who I catch in the games....I've made up my mind :D
There's so many....T_T
Zubat to Crobat, Haunter, Charmander to Charizard, Growlithe to Arcanine, Darkrai, Mewtwo, Magikarp to Gyarados(just b/c you feel so loving towards...