We Without Wings: Masako Takauchi

 Masako is an assertive and somewhat abrasive classmate of Takashi's.  The two end up working on a graduation essay together, although the work is not split evenly.

Aharen-san wa Hakarenai: Riku Tamanaha (Season 2)

  Tamanaha is a kogyaru and former, (and then later) classmate of Aharen. She first appears in chapter 71 of the manga.

Takao Going Barefooted

Why is that Takao Ameku always around barefooted at her office in a general hospital?

We Without Wings: Harue Kasuga

 Harue is a tomboyish crepe vendor who runs a cart called Pal Crepe.  She often uses Hayato's handyman skills.