There are so many illustrators I admire for different things each one of them. x__x
For colour & light: Nathan Fowkes, Dice Tsutsumi and Robert Kondo, and many more
Amazing styles: Claire Wendling, Peter Mohrbacher, Nesskain and many others
Fellow artist friends with amazing skills: Stephan MCgowan, Hunter Bonyun, Elk64, and many others!
There are way too many to list
And some others I don't remember their names....