I've been recently been thinking about Arkane Studio's Prey which is a immersive sim, with a pretty good rogue like dlc, that probably has one of the strongest hooks of any game I've played. If you liked Halflife, System Shock, or Deus Ex it's definitely worth a play.
Are there any titles that might not have been commercially successful that you feel everyone should give a shot?
If you can handle dying a lot while learning the ins and outs of the world, S.T.A.L.K.E.R.: Anomaly is a wonderful package completely for free. Especially if you add the G.A.M.M.A. modpack to it, makes the game play significantly deeper, much harder (in some bullshit and also fair ways), but also just crazy immersive; makes you feel like the actions you take do matter, but if you were to die, you'd just be another loot bag for some other Stalker to come across
I haven't played Stalker but I did finish Into the Radius which is heavily inspired by it.
Oh Into The Radius made me shit myself in fear more times than I'd like to admit
Probably one of the best vr titles I've played. You really feel the isolation.