I did this guest art for @MylCreates' Hacheeachkee , (I hope guest art counts and not just fan art!). 
Also, I know that a lot of creators put their fan art on their profile page where like you said it gets buried. When I get fan art, I always go ahead and put it in to my actual comic as an extra update. The reason I do that is to show my fans I appreciate the fan art and value it, and it also gives love to the creator as I use that to point people to their comic if they have one, or other art if not!