Death Stranding 2 has been a delight to play on the Deck, especially after the performance upgrade patches, though I miss the sounds the PlayStation controllers make when playing it on the PC.

Slay the Spire 2, especially the multi-player, has become a nigh daily ritual for me and my partner to play in bed a bit before sleeping and it runs just perfectly on the Steam Deck.

Ale Abbey is an old tycoon style game about running a monastery that makes all different sorts of beer, with a fairly robust and fascinatingly complex mixture of brewing and economic minigames. And while it's obviously meant to be played on the desktop, it works very well on the Steam Deck.