I like to do a little mix and matching with race ideas. If your doing a scifi game, try to take a fantasy based thing and revamp it in a way that fantasy would do it.
For example: Dragons. Everyone knows what they are but if im in a super futuristic alien setting then what if I introduce dragons as the aliens? Just cause they are aliens doesnt mean you have to change the way they look.
If you read a little into World of warcraft, the orcs are technically aliens. Threw me for a loop x.x