Are there any maps of the Keith Courage underworlds? I have searched online but haven't found any. If not, how would one go about creating them?

I'm not sure of any maps out there, as well. There are probably tools you can find online that would help in creating game maps. But if going a "more manual" route, without any explicit map tools, I'd imagine using something like Photoshop, and though tedious, formulate a "grid" where you can paste screen captures of each part of the underworld map.

Yes, stitching together a bunch of screen grabs may be the only way to go, but that would be very tedious, especially in later levels. I've seen some automapping software for the NES; I was wondering if something like that existed for the TG16. I think it would be really rad to "zoom out" and see the entire underworld(s) at once!