I've spent the last few days spending many hours working on a tool for making, editing, and saving maps. I did it because I was fed up with the system I was using (tilesets) and figured I could make a more efficient model for my purpose that would be easier to use in general.
The way this model works is that there is a map made up of tiles which may contain fields. Fields may have certain properties (whether or not entities should be able to pass through them is the only one currently implemented) that the program interpreting the map may use. Basically, they're rects.
This is essentially the minimum viable product, so consider it an alpha and please report bugs if and when you come across them if you decide to try it out (which would be really cool and helpful). I've tested it with NVDA on Windows.