If you liked the Sword Art Online anime, the Anime-Planet community thinks you'd like:
Rhiannon is the fair and gentle daughter of a village chief. Unfortunately for her, she's also exactly the sort of maiden who is needed as a sacrifice to wake the Demon King Arawn from his thousand-year slumber and is soon kidnapped for this very purpose. However, when Arawn is summoned, he decides to spare Rhiannon's life, instead killing her captor and freeing her from mind control. Taken with his kindness, Rhiannon immediately decides to marry the Demon King, making him the new village chief. All of this is bad news for Rhiannon's protective but hot-headed brother Arthur, who must now pledge his knightly service to his new Lord, Arawn. Together the three of them must journey and together they must fight, encountering new friends and new foes along the way.
The animes Tears to Tiara and Sword Art Online are both one of my favorites! They both are about fighting with swords, not with stupid guns, with both a (in my eyes) good love story. Also, I think that both animes have similar characters. An example: Kirito from Sword Art Online and Arthur from Tears to Tiara. The both have a very strong will and they both are willing to die for someone else.
The power to cross over dimensions is one that is deeply coveted -- a lesson that childhood friends Sakura and Syaoran learn the hard way when an unknown enemy attacks an archaeological dig in their country. As a result, Sakura's memories are scattered to different dimensions, causing her to fall into a deep sleep. In order to save Sakura's life, she and Syaoran must journey to various worlds in search of her memories, with the help of fellow travelers, Fai and Kurogane. But finding Sakura's memories won't be easy, and the price for traveling through time and space is high...
both series feature a male lead trying to save the girl he loves. both anime have complex and well thought out stories while being very viewer friendly in the foul language department.
With war on the horizon, the lives of the students at Tristain Magic Academy are in for a change. As the students train for battle and prepare to join the fight, Louise is determined to protect her childhood friend, now the Queen of Tristain. As her familiar, Saito is sworn to protect Louise and so must ready for battle himself... but with the abundance of pretty girls around, it's a toss-up as to whether Saito should be more worried about enemy attacks or Louise's own jealous rages! Can Saito and "Zero" Louise stand up to the challenge and protect their friends and country?
Both are themed in a fantasy world based on swords and magic. They also have a lead male character with special fighting abilities that they use to protect the ones they love. Both anime's have similar looking characters and they both include humor (more so Zero no Tsukaima), action, and romance. If you love one, you've got to love the other