Tilemap Studio 3.1.0 is out! It has various improvements relevant to both Gen 2 and 3 hacking (binary or disassembly), like proper support for GBA 4bpp and 8bpp tilemaps, and support for GSC Town Map palettes (pic related).
Here's the changelog listing everything new:
https://github.com/Rangi42/tilemap-studio/releases/tag/v3.1.0And a step-by-step guide to creating that Town Map:
https://hax.iimarckus.org/post/48443/#p48443Basically it's an alternative to Tilemap Creator or NTME, for more than just GBA tilemaps.