Monster Brains has a scan of The Official Advanced Dungeons & Dragons Coloring Album from 1979, which was illustrated by underground cartoonist Greg Irons. Isn't it nice when someone makes something much nicer than required?
From the Wikipedia entry on Greg Irons:
After working on the film Yellow Submarine, he returned to work for Graham Productions and soon branched out into album covers and work for the Print Mint, Last Gasp Eco-Funnies, and other local underground publishers. Irons' collaborations with writer Tom Veitch in the early 1970s (the creative team known as "GI/TV") included such titles as Legion of Charlies and contributions to many other underground comix, including Skull Comix and Slow Death Funnies.
In the mid-1970s he started doing book illustrations mainly for Bellerophon Books. One of his books was a coloring-book format illustration of Chaucer's "The Wife of Bath's Prologue and Tale" which was issued with "The Miller's Tale" illustrated by Gilbert Shelton. It was also around this time he began doing tattooing.
On November 14, 1984, while on a working vacation in Bangkok, Thailand, Irons was struck and killed by a bus.
It's out of print, but you may buy a copy on Amazon for $999.97+ $3.99 shipping.