Release | Artist | Title | Notes | Album |
1998 | Kokia | "For Little Tail" | Game Tail Concerto theme song | Road to Glory ~long journey~ single |
1999 | Kokia | "Nesia no Tabibito: Umi to Kaze to Hito no Uta" | TV show Nesia no Tabibito theme song | Nesia no Tabibito Original Soundtrack |
2000 | Kokia | "Sayonara wa Iwanaide" | Anime Karakurizōshi Ayatsuri Sakon insert song | Karakurizōshi Ayatsuri Sakon Original Soundtrack II |
2000 | Kokia & Yoko Ueno | "Currents" | Game Suikoden II image song | Suikoden II Ongakushū Orizzonte |
2000 | ЯKS feat. Kokia | "Goes on Forever" | Released as single, Oricon #70 | Kanata Made |
2000 | ЯKS feat. Kokia | "Kaze" | "Goes on Forever" B-side | Kanata Made |
2000 | ЯKS feat. Kokia | "Melody" | Released as single, Oricon #75 | Kanata Made |
2000 | ЯKS feat. Kokia | "Jiyū na Hito" | "Melody" B-side. | Kanata Made |
2000 | ЯKS feat. Kokia | "Gekitsū" | | Kanata Made |
2000 | Hideki Saijo | "Toki no Kizahashi" | Background vocals. Released as single, Oricon #46 | Planets: 30th Anniversary 12 Songs |
2002 | Vita Nova | "Rom no Aoi Hibiki" | Background vocals | Shiawase |
2003 | Fake? | "Care" | Background vocals | Tomorrow Today |
2004 | Kokia | "Desperado" | Eagles cover, later featured on ' | Hotel Venus Original Soundtrack |
2004 | Kokia | "Bom Bom!! Drive de Kimeyō" | Produced for Toyota Isis promotion, promo only | Tokyo Toyota Original CD Smile & Heart |
2005 | Roppongi Dansei Gasshō-dan Club with Kokia | "Peace Road" | | – |
2005 | Yuri Hiranuma feat. Kokia | "Daiji na no wa Tsuyoku Omou Koto" | | Mada Mienu Eiga no Tame no Ongaku |
2007 | Kokia | "Ai: Wazuka na Omoide" | Anime Red Garden insert songs. | Red Garden Original Soundtrack |
2007 | Kokia | "Katsu: Mabara na Hikari" | Anime Red Garden insert songs. | Red Garden Original Soundtrack |
2007 | Kokia | "Kurenai: Negai" | Anime Red Garden insert songs. | Red Garden Original Soundtrack |
2007 | Kokia | "Shiro: Watashitachi no Hibiki" | Anime Red Garden insert songs. | Red Garden Original Soundtrack |
2007 | Kokia | "Sumire: Hi to Tomo ni" | Anime Red Garden insert songs. | Red Garden Original Soundtrack |
2008 | Kokia | "Anata to Deatte" | Book Girl inspired song | Bungaku Shōjo to Yumeutsutsu no Melody |
2009 | Kokia | "Demon's Souls" | Game Demon's Souls opening theme song | Demon's Souls Soundtrack |
2009 | Kokia | "Return to Slumber" | Game Demon's Souls ending theme song | Demon's Souls Soundtrack |
2010 | Kokia | "Exec_Rebirthia=Protocol/." | Game ' insert songs. | Sakiya=Rumei Ar tonelico III Hymmnos Concert Side Ao |
2010 | Kokia | "Exec_Cosmoflips/." | Game ' insert songs. | Sakiya=Rumei Ar tonelico III Hymmnos Concert Side Ao |
2010 | Kokia | "Hikari no Naka ni" | Game ' insert songs. | Sakiya=Rumei Ar tonelico III Hymmnos Concert Side Ao |
2010 | Kokia | "Kotonoha" | OVA Book Girl Memoire I ending theme song | Kotonoha |
2013 | Paul Ruskay feat. Kokia | "Strike Suit Zero Main Theme." | Game Strike Suit Zero theme song | Strike Suit Zero Original Soundtrack |
2013 | Paul Ruskay feat. Kokia | "Ancient A.I" | Game Strike Suit Zero background music | Strike Suit Zero Original Soundtrack |
2013 | Paul Ruskay feat. Kokia | "Procession of the Lanterns" | Game Strike Suit Zero background music | Strike Suit Zero Original Soundtrack |
2013 | Paul Ruskay feat. Kokia | "Dr. Abram's Discovery" | Game Strike Suit Zero background music | Strike Suit Zero Original Soundtrack |
2013 | Paul Ruskay feat. Kokia | "Earth's Fate" | Game Strike Suit Zero background music | Strike Suit Zero Original Soundtrack |
2013 | Paul Ruskay feat. Kokia | "Unity with the Core" | Game Strike Suit Zero background music | Strike Suit Zero Original Soundtrack |
2013 | Paul Ruskay feat. Kokia | "Credits" | Game Strike Suit Zero ending theme song | Strike Suit Zero Original Soundtrack |