Roguelikes. Binding of Isaac is one of my top played games with something like 500 hours in the game. I put it down a year or two and picked it back up like nothing. Just dodging and weaving and min maxing like i never stopped. Even new games that have a similar feel, I just tend to lock in and end up getting really far in my first run.
This thumbnail sent me on a search to play Space Cadet pinball. I found a web version that works great! Space Cadet
Ive got thousands of hours in POE1 but stopped playing a couple years ago because it started to feel like a cluttered mess. There were so many league mechanics vying for your attention and interrupting the flow of the game it just became tiresome. I hope POE2 feels more cohesive without all the fluff of 50 different leagues. The trailers definitely got me jonesing to play again though.
Hard to know for sure because its been so long and over several accounts/platforms but probably Minecraft. Then Skyrim if you include all versions. Just from steam though its Path of Exile at 700 hours and Binding of Isaac at 575. Those are rookie numbers though compared to the other two.