Guild Wars 2, so far I put 4,800+ hours into it.

I like that it has so many kinds of solo and group content that I can just do whatever I'm in the mood for that day.

Minecraft. Probably have around 5000+ hours I think. Playing since I was 10(now 17). So, many wasted hours on Anarchy Servers and Ranked Bedwars.

Morrowind. Although it's more like play a few hundred hours every five years for me.

I have one game with 1000+ hours and that is Squad. It's the only online game I play anymore as it is the only game that has teamwork/communication (it takes be back to Battlefield 2 days) and none of the shit like battle passes etc.

My gaming habits are just playing lots and never finishing anything... but I have fun still.

Tetris.

Rocket League cracked that for me, crazy ceiling on that game.

Crusader Kings III is gonna crack it eventually…

Rocket League

Somehow ctrl+f failed to find this one, but Path of Exile is probably my drug of choice there. While I raked in 1k hrs with Dota2, I'm not sure I"d recommend it unless you really want to sell your soul to MOBA life. And it's not quite to 1k yet, but honorable mention must go to Satisfactory as it's well on its way to being game #3 in the 1k+ list with me.

Rimworld, and Football Manager (although they last one I played is 2020)

The Binding of Isaac

Garry's Mod. Basically a gateway drug to hobby animation, and in some ways not so far off from the modding tools used to make it.

If you've watched stuff like Heavy Is Dead, they're usually made with it. Some more professional-looking stuff is instead made in "Source Filmmaker".

noita

I'm closing in on 2000 hours, and it's such a great game if you like challenges and discovery.

I started playing it after one of the devs said, "I don't think anyone will ever make another game like it."

It's a terrific implementation of a very pure concept.

I really hope that, despite the development challenge it may present, "noitalike" becomes a thing.

I think it's an engine that would integrate really well with ML world/asset generation, too.

Elite Dangerous. Well over 1,000 hours, especially with friends to explore the black with. Hard to get into, but it has so much stuff to do. It made me passionate about space! (And it's always fun reading articles about a far-flung star and thinking "hey! I've been there!")

Team Fortress 2. There's just so many different ways to play the game with its combination of classes, weapons and game modes!

If you like space games, X3 and X4 can probably eat up lots and lots of your time. Space Engineers if you're less interested in flying, space economics and creating a supply chain (which X lets you) and more in gathering materials and creating all sorts of weird, funny or actually amazing stuff. SE is probably better played with at least 1 other person, possibly more, while X is exclusively single player.

Grand Strategy games can also obliterate your free time. Civilization 5, any Total War game. Hell, Age of Empires 2 can have very long matches if you play on huge maps and people have loved that game for over 20 years.

You can also go for Fallout 4 or Skyrim with extra content mods, like dungeons, quests or areas.

Personally, I'm just past 400h on Palworld, so I'd recommend it as well. I've played from start to "finish" some 4 times by now. Official servers will be wiped sometime in December, possibly with a new patch arriving, but you can always play single player and even invite a friend to play on your local save and never lose progress (unless the save gets corrupted, which can happen).

A long time ago now I spent over 10,000 hours on world of warcraft. I wouldn't really recommend getting into it now though, I think the magic is gone.

I think Destiny is the only game I ever put over 2,000 hours into, but Factorio might take the crown soon - 1800 and counting.

Grim Dawn (currently playing Community Season 7! check it out @ https://grimdawnleague.com/, Dead Cells and Terraria (and most of that time unmodded - i just love building cozy or not so cozy homes).

I've only got a few. Several of them don't really track hours, but I know I've put over 1000 into them. Games like Super Smash Bros. (Melee, Brawl, and 4) and Rock Band 2.

Other than those, the only one I've measurably put 1000 hours into is Skullgirls, but Guilty Gear Strive will likely get there in a few years. Skullgirls is a game with so much depth that I can't imagine ever getting bored of it. If anything, I'd just lose motivation because I can't see the path to improving, but I'll definitely never see every permutation of strategies you can employ by combining characters together. Guilty Gear Strive has so many creative ways to use its expanded Roman Cancel system that any Evo highlight reel is full of creative ways out of situations that you've never seen before.

In descending order: Skyrim Fallout 4 Starfield

Morrowind is a game that has extreme hours too, but not sure if it is 1000+ (yet).

Minecraft...

I've also mostly enjoyed online multiplayer games, but I play a bit of everything. I think these are the games I've played most in order it must be:

World of WarCraft - Been at it since a year or so after it originally launched. Played a lot of Guild Wars 1 before that, and also lots of other MMO games before and in between, but WoW is the one I always keep coming back to. Longest break must've been like 6-7 years around the Cataclysm expansion, and then back at it at the end of Legion. It's on the back burner now again because of another mediocre expansion, but I still check it out occasionally. I think I must've sank at least 5000+ hours (probably way more) into this game over the past 20 years.

Elite Dangerous - Been backing it since Kickstarter, had high hoped for the game and it was fun while it lasted. But I lost all hope in Frontier in managing this game. They're only focusing heavily on microtransactions, currencies and paid early access content now. Must've been about 1500-2500 hours or something, but I've been out of this one for a couple of years now. I had high hopes for the future of this game, but Frontier is a master of promising glory and delivering disappointment.

Squad - Last, but certainly not least for me, around 1400 hours playtime (including the testing branch client). Got into this game right when it launched into early access on Steam. Was very tired of the themepark rides that Battlefield and CoD were turning into, but didn't want to commit to Arma's milsim style either. Squad fits in between perfectly. Also one of the greatest game communities I've got the pleasure to be playing with, never had so much fun with completely random strangers. The mandatory voice-chat really ties it together to create amazing and fun moments. This game really taught me that voice chat in games can actually be good, and not just kids spitting insults.

That said, I have a lot of games on multiple platforms, that I usually won't ever hit a 1000+ hour mark on most of them anyway. Like I played Witcher 3 twice (and a half I think). But that's like only 150 hours or so total. And this year's favorite has been Helldivers 2 by far, but that's only been almost 300 hours so far.

Dark age of Camelot. 6000 hours on my main character. I prefer not to think about how could life be different now if I had not started this game…

Sims 2 Skyrim Stalker franchise (including mods) Doom 2 Vrchat Arma franchise Halo franchise World of warcraft .... I may have a problem.

I am Not even close to 1000h but devinetively Factorio. Be aware, this game is a massive time sink and makes you play for way longer than you want. Especially with the new expansion you can spend enormous amounts of time in this game.