My personal top 4 favorites, in no particular order, are:
- SuperTuxKart
- SuperTuxAdvance ( has a windows download and I'm not smart enough to figure out how to set up and run a version for Linux outside of using WINE or Proton and is pretty WIP )
- Luanti ( specifically VoxeLibre )
- Mindustry ( liked it enough to buy it on Steam to.support the devs )
I know OP already mentioned #3, but you know.
Also, if we could include things like OpenGOAL ( which relies on having files from the Jak and Daxter games ), I'd include that since I just got roughly back to where I left off on Jak II before I lost my memory card. Though that's cheating since it relies on copyrighted proprietary files.