FlyFF - Flyff (Fly For Fun) is one of the greatest running fantasy based MMOs.
Realm of the Mad God - Realm of the Mad God is a best online hack and slash video game that includes pixel style graphics.
Flyff Gold - Flyff Gold is a 2D Fantasy-based, MMORPG and Brower-based video game.
Runescape - RuneScape is 3D Action-Adventure, Massively Multiplayer Online, Role-playing, Fantasy-based and browser-based video game developed and published by Jagex.
AFK Arena - AFK Arena is an Adventure-based, Role-playing and Online Multiplayer video game developed and published by Lilith Games.
LaTale - LaTale draws heavily from some other 2D side scrolling video games to provide a great fantasy MMORPG world.