Phroilan Gardner spent a few years at Blizzard as a concept artist, working on stuff like World of Warcraft and Diablo III, as well as spin-off projects like trading cards and novels. He's not there anymore, but his art - and the stuff he's come up with since - lives on!
Gardner, who now works at Demiurge, most lately contributed to Shoot Many Robots. In the gallery below, you'll find some of his Blizzard stuff, some Demiurge stuff, and some personal art to boot.
You can find a lot more at his personal site.