Well I can revise Chara or Six for this. (The former I might switch to Frisk or Kris) Since Sans is in smash in a way, why not? There's also Villager, and Tempo from Harmoknight. Joker (or another Persona character, noticed Minako in the CS tab), Evie and/or Jacob Frye from Assassin's Creed, even Bow Kid. And even the more obscure ones like Zacharie from OFF, or the Devourer and one of the starter puppets from Shadows: Awakening.