An illustrator whose work should be much better known is Walter H. Everett (1880-1946). Unfortunately, almost none of his original artwork remains. That's because he burned it.
Illustration über-maven David Apatoff presents much of what is known about Everett here (executive summary: he was odd) and Bud Plant has a short take here. That's pretty much it via the Internet if the first couple of Google search pages are any indication. The illustration-related books in my library add little of importance.
Evidence that exists indicates that Everett was capable of creating illustrations of quality that is art museum material. Especially two pieces: The header illustration to this post and the lead illustration in the Gallery section below. I included a few other works that aren't at that level but, as noted, there is little available.
Illustration that appeared in Good Housekeeping magazine.
The two lead illustrations demonstrate that Everett had a mastery of light and color along with skill at placing his brush. To some degree this should be expected, given that he received training from Howard Pyle himself.
Apatoff notes that Everett was a perfectionist. Too bad he wasn't also a packrat.