If you liked the Ar Tonelico Sekai no Owari de Utai Tsuzukeru Shoujo anime, the Anime-Planet community thinks you'd like:
Polyphonica is a place in which humans and spirits coexist; spirits gain their energy from the music of humans known as Dantists. The spirit Corticarte and her Dantist Phoron, along with their friends in the Tsuge Divine Song Players' Dispatch Office, take on cases to help the population deal with problems requiring their unique skills. As they go about their day-to-day work, they learn more about the nature of the cooperation between humans and spirits, as well as their relationship with each other.
Both of these anime have characters who sing songs to use attacks. For me, I had bought Ar tonelico's game before watching the anime, and then watched this particular anime. But while I was watching this anime, it reminded me a lot of Ar tonelico. So, upon finishing Shinkyoku Soukai Polyphonica, it immediately made me want to play the Ar tonelico game again. I'm sure you'll enjoy this in the same way I enjoyed Ar tonelico.
Every year that passes, the lifeblood known as mana which sustains the world of Sylvarant slowly ebbs away. The land itself is dying, fields are turning barren, and life itself is on the brink of collapse. In the quiet country town of Iselia the last remaining hope, the Chosen of Martel, begins the Journey of World Regeneration – a quest which, if completed, would renew the world’s supply of mana and bring prosperity once more. However, Colette is not the first chosen to attempt the Journey; many have already fallen before her. Along with the mercenary Kratos and the half-elf school teacher Raine, Colette must travel to each of the elemental shrines and release the seals so that the regeneration can begin.
Two OVAs inspired by computer RPGs, both Tales of Symphonia and Ar Tonelico will find fans with those who like great tales of adventure and accomplishment. In both, the main focus is on a boy-girl pairing and how they overcome their apparent innocence and feelings of hopelessness in order to win through for their friends.
The stories both see the presentation of mythical worlds where magic, flying machines and dragons may reside, and both act as an excellent companion to the games, but can in fact be viewed independently from the games without too much of a problem except for the rather incomplete endings, which may leave the viewer with the impression that only part of two rather large and fantastic universes have been uncovered. This may, however, inspire and encourage you to pick up the games to take control of the very characters you have been watching, and play out both tales yourself to find out the full story!