What’s your threshold for “old”?
Couple more demanding games / difficult to run at launch that come to mind for me:
Cyberpunk 2077 is about to be 5 years old (2020)
Red Dead Redemption 2’s PC Port is about to be 6 years old (late 2019)
Metro Exodus is coming up on 7 (early 2019)
If this is your first foray into Ray Tracing capable cards, Control makes good use if that feature (Mid 2019)
Shadow Of The Tomb Raider was used as a benchmark for years (2018)
As you start going older than that, even the Steam Deck ends up being very capable.
People had a rough time with Batman Arkham Knight, still looks pretty IMO (2015)
If you’re looking for games that are coming up on 15-20 years old, like Crysis:
S.T.A.L.K.E.R (2007)
Metro 2033 (2010)
Rage (2011)
Doom 3 (2005)
Elder Scrolls Oblivion (2006)