Terraria is there for a few bucks and might be my most played game of all time.
Heroes of Might and Magic 2, 3, 5. These have have given me so much good time since I was a kid gamer.
Some of that good 2010s stuff is on heavy discount. Tomb Raider, Arkham City, Mad Max, Deus Ex HR, Alan Wake.
A bunch of classics are a couple dollars each. like Rollercoaster Tycoon, Blood, Fallout, Indiana Jones Fate of Atlantis, Crusader No Regret, Anachronox, Jedi Knight DF2 (comes with mysteries of the sith), Classic X com series.