Paizo has re-flavored races for Golarion. Space-elves, fey-gnomes etc.
They have some theme-rules too and if fallowed could lead to some interesting situations.
I don't really like playing non-humans myself. Unless they started as humans. Human corrupted into 'something' is my most common character race. All gm:s do this to my chars, there must be something about me.
Ok, but problem is that most players get interestin in annoying steretyphical things. Like kender-thieves have proven.
Alien qualities should be pondered carefully, they must be easy enough to remember and potray by human player. Also, they must be suitable for gaming style. So, if you like playing andventures in fantasy world they should be suitable to act like adventures. Also some races don't do well together, neither do all character classes.
I mostly use unusual critters in scifi games.
For fantasy adventuring games I would create races with features that mostly are about biology. And some culture things. And I would watch out thse wouldn't become game disturbing joke-material. Elves with bad sense of time work well. D&D Karameikos adventuring culture was also unusual coming from humans.
I recently played this guy with curse that caused all kinda crap happen if he stayed in one area for more than 5 days. Very hard to handle during unpredictable adventuring time tables. Had to retire the character, for his inconviniant "bye, but you kjnow I have to leave now, or lands will grow corrupt and darknes will descend"
Watch out for limitations and I would suggest some harsher racial traits only happen when same race critters get together. Even our pet cats and dogs treat us differently than their same race mates. And in some things they (mistakingly) assume us same.
I warn you guys, immature groups get really aggroed by ideas of "mating seasons" and things like that. I still remember jokes about species when this cat-qualities-super-agent tv series was running (forget the name).
