Chris Clairmont's First Flight was good, Peter David is more famous for his Star Trek novels.
Denny O'Neil created Richard Dragon for a novel.
Neil Gaiman is very active outside of comics. Moore and Morrison have dabbled.
I've just discovered Paul Kidd's novel work, and I think I'm enjoying it more than his comics, which were somewhat constrained by the fetish niche of his publishers. Yeah, good luck at Antarctic unless you like Nazis, Furries, or Nazi Furries.
I know there's a few novelists who moonlight in comics, like Harlan Ellison, Michael Moorcock, and Arthur Byron Cover. The Dirty Pair got their start in Japanese "light novels", the first comics were American.
Pat Mills continued Marshal Law in novella form.
Are any of the DC and Marvel novels worth reading? I know Peter David usually manages to make the movie adaptations passable, even getting Batman and Robin to make sense.
Wildcards were cape novels with comic adaptations, but the comics looked terrible. Did anyone take a closer look? Temps was Gaiman's parody of Wildcards when George R.R. Martin told him fuck off.