There are 12 companion pieces in the forms of Fact Files (which expand upon a given character from a corresponding episode) airing shortly after each episode.

Chihiro Enomoto is a freshman that just got to a new school called Rikkyoin High School. He lost his parents in a traffic accident when he was 10. Since then, he has been living only with his elder sister Shinobu. He is good at cooking and cleaning, and does all the housekeeping jobs. He fell in love with Tokino at first sight when he met her in the school library on the first day of school. Another girl named Ritsuko, a childhood friend of Chihiro and the chair of student council, falls in the love with the boy instantly after this long-awaited reunion. But she is not the only one who is in love with him. This is the story about a one-year campaign among the candidates for the next students government leaders, who are also chosen by the lot (kujibiki), in order to gain the position. (Source: ANN)

Second season of Gaikotsu Kishi-sama, Tadaima Isekai e Odekakechuu.

Episodes 13 and 14 of Elf-san wa Yaserarenai. that aired on the web and were later included with the Blu-ray release of the series.