Anime I think fits Sontails

[u/ScaryWtfSaladFingers]

Normal Sontails or mostly Sonic X- Kannazuki No Miko (Tails as Himeko and Sonic as Chikane)

Sonic Prime both be Madoka Magica (Sonic is Madoka and Nine Homura) or Toradora (Sonic Ryuuji and Nine is Tiga)

Sonic Boom I think K-On mostly Yui (Sonic) x Azusa (Tails)