Names that have a link are already taken. If the race name is in red you can't be that race, even if it's a custom character.
Saiyains: Son Goku, Son Gohan,Vegeta, Raditz, King Vegeta,Bardock, Chibi Trunks, Mira Trunks, Pan, Nappa, Bra, Brolly
Humans: Hercule, Videl, Yamcha, Tien, Chow Su, Krillin, Chi Chi, Ox King
Nameks: Piccolo, Dande, Nail, Kame, Lord Slug
Aliens: Majin Buu, Cell, Frieza
Androids: There will be a maximum of fifteen androids at any time. They can be numbers, names, whatever. They are the only race that all start with a special attack. They start off with 'Absorbtion Force.' When they use it they can grab onto someone and drain their ki. If they hang on for the whole fight their maximum ki level goes up. Determining whether or not an android hangs onto you uses a similar formula to dodging except it uses Strength and not speed. If you break loose the android will be unable to dodge your next attack or counter it with an ki-duel attack. Below this I will list androids currently being used.