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?
Titanfall 2
Definitely didn't get the appreciation it deserved on launch. I seem to remember it was launched right after that year's Battlefield and right before that year's CoD. Terrible decision. It definitely stood the test of time though and is very highly regarded now.
Titanfall 2 definitely got a lot of appreciation.
It needed more.
Bought the game at Dollarama in Canada for $4 a few years ago. Still haven't played it.
The campaign has some absolutely wild parts of it. It's worth playing through that if nothing else