It’s no secret that I am a big fan of Arthur Rackham. His technique lends a credibility to the notion that his characters existed before time. I have an old edition of Aesop’s Fables Illustrated by Rackham which is a cherished possession.
Here is a link to a google search of his images. Here is a link to JVJ Publishing site with a nice bibliography section on many old school illustrators, cross referenced with their influences. Neat.