Post plain/nerdy/rustic girls.

They often have glasses, braided hair, twin tails, unkempt hair, light skin, flat chests, large breasts, slenderness, chubbyness, pubic hair, school uniforms, books or computers.

Think of characters like Hanekawa Tsubasa, Yuki Nagato, Tsukimi Kurashita, Homura Akemi or Sumireko Sanshokuin.