zip package: https://gitlab.com/h2mm/minetest/-/arch ... inbrot.zip
GitLab branch: https://gitlab.com/h2mm/minetest/tree/terrainbrot.
After that you can see the "terrainbrot" as one option. Windows users can download the (currently outdated) build here.
Warning! The settings are currently subject of change. If you download a new version of terrainbrot, reset the settings to default.
This mapgen is based on the "fractal" mapgen. It iterates a rational function and uses perlin noise to generate stuff endlessly. Its variety is very huge. It can generate anything from flat lands to insane mountains. It also generates rivers. Some areas are full of rivers, other areas contain no rivers at all. Some rivers are straight, other rivers are curly.
It is not supposed to be a realistic terrain. I focused that on being simple and using a lot of variety. However, there are many places those look very realistic. I think, it might be also a good fantasy world.
Some screenshots: https://imgur.com/a/HSv5oCN
A short explanation of how it works: