I largely hate doing backgrounds, but it makes stuff look sooo much better! I mostly use 3D for backgrounds these days, unless it's organic. I have a bunch of favorite background artists! There's so many amazing artists, but these are some cool guys that do memorable backgrounds that I can think of right now, lol.
Dan Panosian always has this nice loose sketchy style which I really like.
Jack Kirby had a funky style, that made for some really interesting and unique locations.
Dreamy P. Craig Russel
Mike Mignola, the graphic shadow master.
And here's Bernie Wrightson if you feel like crying today, lol