A Work-In-Progress ECS (Entity-Component-System) based cross-platform game engine, written in pure C#. The engine is still in early stages (especially due to the recent rewrite to ECS), but anyone is welcome to try it out and provide feedback. Just note that documentation is nearly non-existent.
A game template repository can be found here:
Fork it, clone it, ensure that submodules were downloaded correctly, and rename whatever you want to.