I think that while base game should stick to "weird alien look", with DLC you should focus on looks that you cant put in base game. Not everyone will like all of them but point is that everyone can take what they want. Not everyone will always have serious playthroughs.
-Fantasy races(elves, dwarves, orcs, goblins etc)
-Animals(cats, dogs, bears, dolphins etc)
-Mythological creatures(dragons, gorgons, harpies, unicorns etc)
-Anime humans(human diversity anime style)
-Races from various science fiction franchises(star trek, star wars, alien vs predator and numerous others)