Disclaimer: This is MY OPINION. Feel free to disagree or agree.
Top Tier: (1-11)
S| Rosalina and Luma, Cloud, Sonic
A| Sheik, ZSS, Diddy Kong, Fox, Pikachu, Mario, C. Falcon, Corrin, Ness
High Tier: (12-25)
B| Bayonetta, Mewtwo, Mega Man, Villager, Pit, Dark Pit, Luigi, Meta Knight, Yoshi
C| Peach, Falco, Greninja, Ike, Mii Brawler
Mid Tier: (26-37)
D| Lucas, Kirby, Toon Link, Bowser Jr., Link, Marth
E| Lucario, Shulk, Donkey Kong, R.O.B., Wario, Robin
Low Tier: (38-48)
F| Roy, Mii Swordfighter, Mii Gunner, Olimar, Wii Fit Trainer
G| Lucina, Dr. Mario, Little Mac, Bowser, Pac-Man, Palutena
Bottom Tier: (49-56)
H| Duck Hunt, Zelda, Samus, King Dedede
I| Ganondorf, Charizard, Jigglypuff