Whenever your birthday comes up, you're allowed to request the addition of a level 5 basic stage Pokemon for your team! Just post here and you'll be updated.

Pokemon you cannot request:
Legendaries
Starters
Snarliger
Atlaxa
Flintusk
Allufang
Purior
Mirust
Goldrake
Khaphix
Leoracle
Kraklaw
Blitzfaust
Vilephist

Anything else is fair game, including canon Pokemon that are part of the Topaz 200.

I guess that's a lot of exceptions... oh well!