Final Fantasy 14. Last time I checked I had at least 20 days of playtime on my character, which is somewhere around 500 hours.
Monster Hunter. Honestly while I enjoy World, it's not my favorite and I'd have to say that would be 4 Ultimate. Lost track of how long I played it, but when I figured out how to use an editor to make custom quests it was basically the only game me and my brother played for one summer.
Dark Souls 2/Bloodborne. My two favorite Souls games, between them I've probably got at least 100 or maybe 200 hours.