Alan Moore (who I've posted about twice (#490704 and #511196) and really need to get back to writing more about) is generally regarded as one of the two or three best writers in comics, and has also written stories, novels, and more. He's made the course he originally developed for the BBC available for free online (though it looks like the written bonus notes would run you an extra $11 at Gumroad). I've only started to dive into this, but it's already fascinating as a fan of his work, and would probably be valuable for any fiction writer.