I had a friend at one point who played on a large OpenMW multiplayer server that functionally acted like an MMO, but I was never able to find anything like that on a quick search.

Also Nuclide being listed as GoldSrc on that list, but Xash3D only as a single game "Half-life 1 engine" (A.K.A Golsrc) feels somewhat odd. That, re3, and of course the id software ones are quite nice.

Do you think https://github.com/N64Recomp/N64Recomp should count in that list as a multi platform source port?