Thanks for starting the thread Henri ! Waxwork and me have tested quit a few, and we were working on a review of some of them.
This is my opinion about some anime mmo's I've played.
Ragnarok online by Gravity
Ragnarok is a classic among the f2p anime mmo's, it was first released in 2001. The game is partially based on Norse mythology and is set in a 3 dimensional environment, except for the avatars who are 2 dimensional. Pvp is an important part of the game. Guilds can win control over a castle for a certain period of time by winning a war between guilds. The winning guild also gains access to a special dungeon where they have the chance of dropping rare items. A sequel for the game is being developed.
: there is still a lot of interest for ragnarok.
: the game is old school, it's time for that long awaited sequel : Ragnarok The gate of the world !
Rose online by Gravity
Players are in a rush to discover the different planets on rose online. Travelling by cart, and for the lucky few by castle gear, visitors start their journey on the planet of Junon to protect the worlds against the evil Hebarn and his followers. Interplanetary travel is possible by using a flying vessel to continue the battle on the cold and icy planet Luna. At higher level the journey ends for now in the jungle of Eldeon, the third planet.
: this game is not so known as ragnarok online so you must not expect a large server population
: the game is very attractive but it's a shame there still are a lot of maps missing. Development isn't Gravity's strongest side.
ROSE Online: The Official Site of ROSE Online North America
Atlantica online by Ndoors
Atlantica online is a turn based mmo where you get up to nine mercenaries to help you out in battle. You can still group with up to two other players. The gameplay reminds me bit of Final Fantasy VII. Your adversary does all his attacks in one time which is good if you don't like waiting. Except for dungeons there is no aggro in this game untill high lvl. The main quest is well worked out and crafting is important in this game too. Pvp tournaments are a big thing in Atlantica and fun because of the turn based gameplay.
: well populated
: The turn based gameplay is a nice change from the usual type of Korean mmo's. It makes grinding a lot less boring too.