1. Apes who capture humans.
2. White looking humaniod aliens who capture other races and make them their own.
3. Robots from a long destroyed civilization, still serving their missing of killing everything.
4. Large number of insects.
Now for some races that I put some time into:
5. A twisted Knights Templar. Ones who kill those who don't agree in their religion.
6. A future version of the Nazi's or KKK. Same mission as above.
7. Robotic beasts that we'd call animals, who gave themselves technology and are free thinkers, hating any form of control.
8. Ghouls who regave themselves partial life back thru computers. Only way to kill is thru special weaponry (IE plasma).
9. The abandoned, a large number of intelligent men who slowly mutated into horrific creatures after being left in radiation in the far depths of space after losing a battle.
10. The militants, a collection of people from south america, the middle east, china, and africa, who use sneak attacks to gain technology due to their little technology. Large numbers.