Thanks for the suggestions. I'd not heard of M is for Monster before, but I'll take a look. Strange Planet is something I enjoy, and not to quibble too much, but it's not really a "graphic novel," but a collection of strips.
As an alternative, I'd suggest the modern classic Nimona by ND Stevenson, which was adapted for film and released just last month on Netflix. I'll go ahead and post samples in a new post.