How do I search for games that support Oculus Rift?

Thanks dude!

Sadly, GOG doesn't prioritize VR. But I did find a few titles:

P·O·L·L·E·N - According to Steam, this one works on Rift.
The Solus Project - According to Steam, this one works on Rift, and touch support should be in the works.
Sublevel Zero - Tried it, works on CV1. (as usual, not mentioned in the description)
Mind: Path to Thalamus Enhanced Edition - When I bought it, It did work on Rift, as they promised .. but they failed to mention that it required Touch controllers which wasn't commercially available at the time! ... but now that I got my Oculus Touch, I might finally get this one to work!

There is far more VR content on https://itch.io/ - but this is more of the 'indie playground' varity:
https://edgeofprophecy.itch.io/sploot (pretty fun!)
https://rawlionworkshop.itch.io/alqom
https://michaelschenck.itch.io/lost-loot
https://exequor.itch.io/final-shift-vr
https://bunnygun.itch.io/masquerade-mystery-vr
https://blackwolf.itch.io/vrtheatre
https://itch.io/e/260525/plumpsheepie-created-smallfire
https://demonixis.itch.io/mars-extraction
https://crovax-studios.itch.io/ancient-vr-coaster
https://madsoft.itch.io/vrninja
https://ponyhypetrain.itch.io/rainbow-quest
https://crovax-studios.itch.io/ancient-vr-coaster
https://madsoft.itch.io/vrninja
https://circuitwarz.itch.io/circuit-warz-vr-simulator
https://exequor.itch.io/theyre-trying-to-ram-us-vr

Also, there is loads of old titles on GOG that are supported by vorpX:

Alan Wake
Amnesia
Amnesia – A Machine for Pigs
Assassins Creed
Darksiders
Darksiders II
Dragon Age: Origins
F.E.A.R
F.E.A.R 2
Legend of Grimrock
Legend of Grimrock II
Mount and Blade: Warband
Metro 2033 Redux
Metro Last Light Redux
Miasmata
Outlast
Q.U.B.E.
Quake II
Quake III
Race Driver GRID
Risen
Risen 2: Dark Waters
Risen 3: Titan Lords
Shadow Warrior [2013]
Slender
S.T.A.L.K.E.R.: Call of Pripyat
S.T.A.L.K.E.R.: Clear Sky
S.T.A.L.K.E.R.: Lost Alpha
Star Wars – Jedi Knight II – Jedi Outcast
Star Wars – Knights of the Old Republic
System Shock 2 (with DX9 mod)
The Ball
The Vanishing of Ethan Carter
The Witcher 3
Trine
Trine 2
Vampire: Redemption
The Witcher
The Witcher 2