Sakura and/or Elise (Fire Emblem Fates): Remember what Isabelle did when she was an Assist Trophy? She healed you by throwing food at you. Sakura or Elise could wave their cute staffs or something. Just an Assist Trophy I need in my life.
Futaba (Persona 5): Warps around stage, warping enemies far off of the stage. Cannot be KO'ed, because for the love of Jesus, waifu is laifu.