These are made for X86, so I'm not sure they technically count as "old games", but I've had a blast with recompiled+ported versions of TLoZ:OoT and Perfect Dark.
Ship Of Harkinian in particular adds so many features and improvements, that I'm not sure I would enjoy the original OoT played on an actual N64.
I tried playing Perfect Dark on N64 again during the pandemic. Single player was great, multiplayer runs at like 12 fps and I have no idea how I ever played it as a kid.