I collect:
Squirtle Line
Totodile Line
Zubat Line
James/Team Rocket

My HeartGold/SoulSilver team:
Totodile, Mareep, Zubat, Growlithe, Dratini, Larvitar (and their lines)

My White Team:
Pansage, Scraggy, Oshawott, Joltik, Venipede, Woobat (and their lines)

Side Collections:
Other starters: Bulbasaur, Charmander, Piplup, Mudkip, Oshawott and Tepig
Bug Pokemon
Dragon Pokemon
Purple Pokemon
'Cute' Legends

I prefer plushes, but I like Zukans, Kids and Tomys too
but if you have just about anything from my "main" collections chances are I want it :D