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?
Mannnn. Outer Wilds is so freaking good. I had put it off for a while, but then last year I decided to go through it. It managed to be the perfect game at the perfect time. Raw intrigue and fascination turned into somehow helping me cope with the loss of my sister and dad who I had lost very recently at the time.