If you like Doom, there is a completely libre remake of the art files, which
runs on top of the GPL engine, called Freedoom:
https://freedoom.github.io/
I quite enjoy the libre remakes of some games I used to enjoy in the 80s on
Commodore 64 and Amiga, including FreedDroid (classic not RPG, based on
Paradroid), Epiphany (based on Balderdash), and Pingus (based on Lemmings).
Defendguin is fun for a few minutes every now and then. Sadly my laptop
doesn't have powerful enough graphics chips for anything more than these
proof-of-concept toys. All the really juicy games like 0AD won't run.
