Maybe you people have found this already, but I thought I'd share it.
Many of the mods on that site work well with Pimax, especially Doom, Doom 3, and Quake 2. I have tried and failed to get Duke Nukem and Jedi Academy working but have yet to try the latest beta. Dolphin VR is absolutely stunning. I played Eternal Darkness in VR and it works really beautifully well, but the zooming camera is pretty nauseating.
Richard Burns Rally is great too.
If anyone knows of any other old classics that have been given new life, please let me know.
Edit: This is great too. Just managed to get Wipeout Pure working in VR. (with the Revive Injector)
Edit 2: Resident Evil 4 on Dolphin is also pretty amazing, once you get rid of the black lines (game Properties> Hide Objects)