http://www.pathofexile.com/
free to download, free to play, no pay2win, only cosmetic items for sale, and players seem very eager to support it by purchasing cosmetic items because they enjoy the arpg so much. an arpg with good leveling, good end game, good itemization, good community, good support from developer, etc...
Yes, I play PoE since open beta (january) and I have abandoned D3 since then mostly.
PoE has much better itemization, better and tons more of skills and it has not a skilltree but an skillforest. ^^ Updates and improvements almost every day, new Unique Items regulary, user designed Items (for $1000 by the way
) and NO Auction House!
Ok, it still has many flaws, not so smooth gameplay like D3, performance, desync and lag issues and a annoying trading system over chat. However, they provide ladders and many different "race" events, various leauges where you can win prizes at the end etc...
I've spent some Euros in this game but only for my stash expansion, fair price, alot of personal benefit but nothing that impacts gameplay.
The most popular F2P besides LoL is of course World of Tanks.
http://worldoftanks.com/
I've played it some time ago, it's now much more popular and has tons of new content, real physics, less Pay2 Win than in the past but still the same weird matchmaker. I quit for a good reason, random matches are, well, random and you can be sure that the matchmaker will set you to the looser team, there are many threads about the matchmaker, it seems its manipulated and mainly for keep your win/loose ration 50/50, no matter how good you are.
There is also World of Warplanes but people say, War Thunder is much better and more fun, you even can play it Single Player.
http://warthunder.com/