I think the obivous choices would be:
-Humans/Elves/Dwarfs (individual or a collective like in other games and books im not sure)
-Undead (my fav choice and I vote for these guys)
- Evil version of Humans/Elves/Dwarfs?
Maybe a race based on subspace or the place between worlds?
Example being http://leagueoflegen...m/wiki/The_Void
(sorry I don't mean to link this but it's the only place that can adequatly describe what I mean.)