The Veloren developers just released a quite extensive tutorial for using their experimental plugin API. Might be a cool thing to experiment with and see what can be done.
https://book.veloren.net/contributors/modders/writing-a-plugin.html
The plugins are sand-boxed and downloaded on connecting with the server, which some will see as an anti-feature, but I think the long experience with doing that on Quake1 engine shows that this is a good way to avoid game-play monoculture and bring about a lot of creativity.