I was going to say replaying but I feel like that limits the question to games like Prey or Fallout New Vegas that have endings and games like The Sims 2 or Cities Skylines where you can play indefinitely end up excluded.
I’m not really referring to games like League of Legends where you’re coming back every month. More so games where you stop playing for an extended period of time.
Cataclysm: Dark Days Ahead, Dwarf Fortress. Highly-replayable, open-world and they keep being developed, so when you come back, there’s new stuff.
Skyrim, Fallout 4. Same idea, but the modders have added a lot of content.
Some of the city-builders, like Tropico 5. I play for a while, get tired, uninstall, but tend to come back, because the game is replayable.
Chase the Sun and Nova Drift are action games that I have spent some time away from and then come back and played. Nova Drift has seen regular development.
Pinball sims. I think that one can only play so much pinball, but I find myself thinking “I’d like to play a pinball game” down the line and reinstall.
I think that most of the games have some common characteristics:
Didn’t live-or-die based on their technology or graphics, because they’re invariably obsolete by the time I’ve come back.
Need to be highly-replayable. I’ve played games with story, like Fallout: New Vegas but I don’t really go back to play them for the story (though I’ll concede that specifically Fallout: New Vegas does have multiple paths to explore). They can’t be appealing because of a surprising or tense plot or a plot twist.
Often see continued development or modding, so there’s some reason to go back and see what’s there (though pinball would be a notable exception…you don’t go back for new content).