The Doomlien is a main staple.
This lovely reference image is courtesy of: @TheWeirdling
Doomliens can be found everywhere.
The Outfit
Doomliens wear Jumpsuits
Jumpsuits are a common across most Doomliens. Some occupations may have variation on the suit's colour or design. Some Doomliens wear entirely different outfits due to their specialized job that requires protection, or carries significance reflected on the different outfit.
Purpose
It's no mystery that Doomliens are an integral part of their society.
Often times if a problem occurs a Doomlien might be held responsible for it.