Aion, Everquest 2, Neverwinter, Rift, and Tera are all fantasy MMOs that have free to play access. Not sure what their F2P plans are like, if they're very limiting or whatever, but I think all of them allow you to play to max level without paying anything. Lord of the Rings Online has some free to play, but I think it has a level cap and you have to pay to go farther.