Two OVAs released with the 8th and 10th volumes of the original novel. They fall chronologically between the first and second seasons.
Up to EP 12Aguu: Genius DollsAnime
Up to EP 12Punch LineAnime
Up to EP 13Hanebado!Anime
Up to EP 13Gargantia on the Verdurous PlanetAnime
Up to EP 2Terra Formars: Bugs 2-henAnime
Up to EP 3Phantom The AnimationAnime
Up to EP 1Wolf Girl & Black Prince OVAAnime
Up to EP 12Real Girl Season 2Anime
Up to EP 1My Neighbor TotoroAnime
Up to EP 12Fist of the Blue Sky: RegenesisAnime
Up to EP 1Whisper of the HeartAnime
Up to EP 26Xam'd: Lost MemoriesAnime