I'm not an online multiplayer gamer, I mainly play single player no competitive games (aside of SFV, which I like, a lot, but don't play online too often because I don't trust my internet connection enough).
Anyways the three games with more hours played this year are:
1. Dragon Quest XI: Echoes of an Elusive Age: 128 hours. No surprise here, since JRPG's are usually long games. Now there is a definitive edition on Steam Store though, so if you plan to play it, best get the upgraded version (though it's kind of downgraded in the graphics section).
2. Contra: Rogue Corps: 81 hours. This was a surprise indeed, since I found that this game is greatly underrated. It is overpriced as well (I got it for 10€, I wouldn't pay full price for it). The loot and upgrade system are great, and the game mechanics pretty fun.
3. Agents of Mayhem: 73 hours. It's like a baby from Saint's Row and G.I.Joe. It's patent the love Volition put into it, but it didn't end well enough.