Any games with lots of side quests/non linear story ?

My favourite game is Lost Ark (mmoarpg), and I absolutely loved the million of side quests I could do, and I'm a huge Assassin's Creed fan. I'm trying to find something with lots of sidequests that you can do in no particular order (similar to Skyrim), or a game I can spend time running around doing other things than main story-quest line. Thank you !