I love strategy games that make me think and that I can keep coming back to, and also anything I can play with friends and family. If I had infinite time I would play Factorio and XCOM to death, but alas, I do not. Incremental replayable games like Slay the Spire and Stardew Valley fill my free time very well. Civilization is a classic I always come back to, as its easy to fit in and come back to a save after months and pick right back up.