Right this hasn't been updated in awhile so i thought i would take the opportunity to do so since i believe alot of people are missing out and great free to play games, so hear it goes
Lets start with
Tera Rising, Formerly Tera Online but now FTP with a cash shop system...this is really worth it guys the battle systems takes away from "Auto-Battle" and puts it in the hands of players who can actually avoid being hit all together
Pros: FTP, extremely fun especially while soloing, Money is easy to make, Leveling is steady and does not require "grinding" to accomplish, Gigantic open world, extremely wonderful graphics. End game equipment is rather easy to get but takes awhile.
Cons: While you can fully solo your way to Max level 60 there is not much to do except raids which become distasteful and repetitive and require good teamplay to become viable.
Your require a tank healer and dps for raid like any other rpg out there and become dependable on your party members doing their part flawlessly.
If you play any class beside tank you can find yourself queued for hours to do dungeons so best to have guild support for this.
Second on the list there is
Path of ExileThose who liked Diablo style would love this. IMO this game shits all over Diablo 3, this is what a game like this was suppose to be.
Pros:FTP, Unique skill tree system, Unique ability system, Can be soloed, Extremely long content, Parties are easy to find, Equipment easy to get.
Cons: Extrreeemmmmly long if you are soloing get a friend and play this. Can be repetitive at times. The simple misclick on the skill tree can turn the tide in the level you are playing and cannot be reverse until lategame or use of cash shop so best to use a guide
Anyhow this IS the true Diablo
Thirdly
Absolute Force online for those who like shooters, this game utilizes the unreal 3 engine
Pros: FTP, fairly straightforward interface, Unlockable weapons as you progress, Alot of different modes deathmatch, zombie mode CTF etc.
Cons: Players who actually spend real money to buy weapons will have access to the best their is and give them a slight edge
I have more to add but im tired of typing so i'll update later