Dear Brother / Oniisama-E

Genre: Anime, Shōjo, yuri
Link: Youtube Playlist
Series Description: The story is about a 16 year-old girl Nanako Misonoo who attends a prestigious girls' high school and falls into a world of female rivalry, love, chaos and heartbreak. Nanako is left to protect herself from rumors and mean plots to make her leave the school. Along with her best friend since preschool, and new friends made along the way, she uncovers the past of some of the more popular girls in school and on her journey through highschool she learns of love, loss and her family's secrets...

How is it for its yuri content? See Yuri no Boke.

Notes: I didn't know there was an official Youtube channel release of this series! I remember masaka lending me a copy which she digitized herself from her VHS machine, years ago, as it was pretty rare. Super classic yuri! Looks like the videos even have different language subtitles. :)