Lord of the Rings Online - Has gone free to play. You buy cosmetic items, potions, content/quest packs from the cash shop.
Dungeons and Dragons Online - Also free to play. You can buy extra races/classes, potions, content/quest packs from the cash shop.
Runes of Magic - Free to play WoW clone. Very popular with your typical F2P cash shop.
Allods Online - Russian F2P title. It's steam punk/fantasy. Last I heard, cash shop is a little pricy compared to other F2P titles.
EverQuest II - Has both a premium subscription version and now a F2P version. Cash shop to unlock extra races and classes plus content/quest packs.
Alganon - Another F2P WoW clone. Was launched as a full sub mmo, but failed badly. Is now F2P.
Forsaken World - From the developer of Perfect World / Jade Dynasty etc. Their take on a Western Fantasy styled MMO. Is in open beta now I believe.
The ones in bold I recommend to check out. All are fantasy mmo's but not exactly like FLYFF. There's a lot more F2P fantasy type mmo's. I haven't listed any of the Korean ones, like Aika, Archlord etc.
For titles more similar in art style to FLYFF, ie anime like, maybe check out Dungeon Fighters and Rusty Hearts.