Illustrator and artist Erica Lee has drawn up character studies of a few of the races in the Mass Effect universe, like some of those seen in the latest game in the series, Mass Effect 3.
The characters studied in the illustrations include Salarians, Asari, Drell, male and female Turians, Krogan, and Protheans.
Absent from the list are the dozen or so other races in universe, but that's okay. The characters were mostly drawn up from their representatives on the Normandy. The artist figures that the illustrations were drawn up by Dr. Chakwas and Mordin for scientific and health-related purposes.
She writes: "I’ve always wanted the chance to draw Mass Effect’s gorgeous aliens in their ‘full glory’. Yes, I am one of those people that thinks that Javik could have wings because the Collectors did. Kirrahe is here because he is a spectacular example of his race. The nips were left off Liara because of personal censorship and laziness. Sorry if an alien race you like was left off the post. In the meantime, have some alien butts."
So there you go. The rest of her work can be found on her Tumblr blog.