I have tons of games on Steam I forgot to have them. In example I forgot that I had Skyrim and never played it. I've tried it this year for the first time in my life, just to see how it is. And immadiately could not play it, because the intro was bugged and I thought its a puzzle I had to solve. Took me until I understood that I had to limit the fps to 60, because Skyrim is buggy if you play it on a 120 Hz monitor.

I've had a lot of games that I found online, thought they looked fun, then discovered I actually had them in my steam library already and never once touched them.

Geometry Wars is fucking awesome. I still remember playing Project Gotham Racing 3 on my 360 as a teen and discovering the Geometry Wars arcade cabinet in your in-game house that just lets you play the whole game.

For me, the most recently, probably Dishonored. Id played it through before, and really enjoyed it, but never thought about replaying it until I saw it in my library again. So I replayed it, and goddamn it, that's a great game still.

I never forgot that I had Warframe but I just got back into it after 7 years of not playing and it's still great.