Mass Effect. It's sci-fi and has different types of aliens, most rather humanoid (bipedal, one head, mouth, two eyes), but not all. It isn't my first fandom with aliens either, but one main character (Garrus, a turian) was really hard on me, while the all-female asari were not. I didn't even attempt to write a hanar (walking pink squids) or an elcor, which would be even more difficult.

Some big fandoms (like the Stargates, Star Wars) have a lot of aliens, so I guess it's telling that the concept is so underrepresented. I think maybe the aliens aren't meant to be too alien, or maybe popular (centemporary) sci-fi doesn't explore the possibilities so fans don't either.