For me it was Terraria, Satisfactory, Tetris Effect Master Mode, Minecraft with Mekanism mod & CSGO / CS2 (almost 2000 hours in CS alone).
Edit: There are so many answers that I might only reply if I have something interesting to say. I will read all of your answers though. 🙂
Edit 2: It has become too much for me and I have to disable notifications. Thank you for the massive response and please continue to discuss with everyone here. ❤️ 🫡
I've only played like 8 leagues (each league is around 3 months long) and I have almost 5k hours :/.
Usually if I decide to play a league, i will make sure I have no obligations for an entire month and then I will take the first week of the league off work.