Games

Does Mbin count? =P

Jokes aside, imo, Skyrim, Starbound and Final Fantasy XII are great games to sink a long time. Of those, Skyrim I played the least due to life happening, but was enough to sink a few dozen hours already. Starbound easily surpassed the 600 hours for me, even if I barely use mods or played multiplayer. And Final Fantasy XII, on my first save I got to the final boss, I was nearing 300 hours already, and for a game originally on a 4.7 GB disc, it has a lot to do, so much so that, in that save, I was just starting to scratch past the surface.

Factorio: 1,400 hours
Fallout 4: 1,100 hours

I have a lot more hours on Counter-Strike Source than that, but that was before Steam started counting hours. I also played a ton of Sims 2 and 3.

Literally thousands of hours in stellaris and space engineers. Recently satisfactory as well.

When I was younger I also played a metric fuckton of world of Warcraft, though that thankfully is a lot less addictive nowadays.

Binding of Isaac: Rebirth and Civ 5. Those two took over my life for a while.