What is your favorite Free To Play (F2P) game?

So recently I was thinking about free to play games and how a lot of them include the stupid Pay to Win feature just to make a profit. Then I was thinking about all of the free to play games I have played and how many there are out there, and was wondering what are your favorites and what are the ones you like the most. Right now, I love Black Squad, due to it being a non Pay to Win game with a Payment feature that I barely know how to use. But there are plenty of them out there, and I was wondering which ones were you favorite and why they were your favorite. For me, Black Squad is a good arcade shooter like Call of Duty, and has a good element of tactics like CS:GO. Hopefully they add more weapons and work on making or implementing an Anti-Cheat system soon, because even though it is only been out for about 3 weeks, I have come across a couple of hackers already. Anyway, What is your favorite Free to Play game and why? If I didn't put yours up there, comment what it is, and why you like it!