Pokémon High School (ポケモンハイスクール) or also known/tagged as Poké-High (ぽけ高) for short, is a pixiv project managed by シュウ and another pixiv user about a high school where the students that attended and teachers are all Pokémon (both anthro and feral)
The project was held from July 14th 2012 to July 14th 2013 (during the final years of Pokémon's 5th generation)
Project's main account
Manual book (in English)

(For more accurate information, visit dic.pixiv.net)