i'll give you a quick run threw...
1st gen: Psyduck (perferbaly Shiny)
2nd gen: Totodile, Umbreon, Octillery, Tyranitar
3rd gen: Metagross, Walrein, Bagon, Latias
4th gen: Gible, Hippopotas, Mismagius
number one favorite: Psyduck
(always and forever... i can't belive people hate him..)