During the development of Cat's Tonk Game, I've made a terrain editor. This Terrain Editor can be used to make heightmap based terrains with textures for Cat's Tonk Game.
Controls are simple, left click to click things or use the tools, alt to rotate the camera, mouse wheel to zoom in or out, and wasd to move around the terrain.
Known issues are listed in the readme included in the download.
If you end up making a terrain and want to submit it, contact me directly!
Current Version: v0.3