Do enjoy this list (ALl these are games i have played b4 and are still free):

www.runescape.com
This game is so called "3D" .. although i looks like it, i don't feel it is 3D .. this is a quite a fun game actually. I played this game actually 2 years back. You can do lots of things like mining, blacksmithing, fishing and there are many quests in this game. Very typical MMORPG .. You can PVP in wilderness too, very fun, especially when you kill someone and get all his loot ..

www.maplestory.com
This game is a side scroller MMORPG and the gfx are very cute and lovely ^^..You
can choose 4 different type of classes: Warrior,archer,thief and mage. This game is 2D and it is kinda fun, but all you can is kill monsters, there are group quests and there is no PVP in this game.

www.gunbound.com
This is also another side scroller 2D game, but it is different from your typical MMORPG. This game is something like the game "Worms" , if anyone knows what it is .. you can play 1 vs1,2vs2,3vs3 or 4vs4. The graphics are quite cute and pleasant.

www.roseon.com
This is currently a new 3D MMORPG in beta. Translated from korean.. it is made by the company gravity which also made Ragnarok Online. It is very similar to ragnarok just that it is totally 3D , i have not played much but i know alot of people who enjoy this game. Another typical 3D MMORPG translated from korean to english .. again no PVP..

http://www.darkeden.com/en/
This game is 2D and it is about vampires VS slayers. lots of PVP content in it.. it's all about vampires fighting slayers and there are often raids etc. I would suggest this game for gamers who likes to PvP ..

http://www.eternal-lands.com/
The game is now in Beta stage, but that doesn't mean it is incomplete and it plans on being free. There are 9 skills, total character development freedom, many quests, religion, a lot of NPCs, animals and monsters. If you are a PKer, you can fight other PKers in special maps. If you are not a PKer, then you can stay on the non PK maps, where you don't have to worry about being attacked by other players.You can fight monsters and other players, hunt animals..

Please continue adding to this list if possible ..