A/N: This all purely opinion based

Izuku Midoriya MU tier list

The One: Gon Freecss (Hunter X Hunter)
Good alts: Atsuko Kagari (Little Witch Acadamia), Rock Lee (Naruto)
Fine?: Will Stronghold (Sky High)
Meh: Miles Morales (Marvel), Boruto Uzumaki (Naruto)
No Thanks: Izuru Kamukura (Danganronpa), Ms. Marvel (Marvel) Spider-Man (Marvel), Monkey D. Luffy (One Piece)

Tanjiro Kamado MU tier list

The One: Jonathan Joestar (Jojo's Bizarre Adventures)
Good alts: Hyakkimaru (Dororo)
Fine?: Edward Elric (Fullmetal Alchemist)
Meh: Yuichiro Hyakuya (Owari No Sereph)
No Thanks: Doomguy (Doom)

Aang MU tier list

The One: Aether (Genshin Impact), Lumine (Genshin Impact)
Good alts: Yugo (Wakfu), Aladdin (Magi)
Fine?: Captain Planet
Meh: Po (Kung Fu Panda)
No Thanks: Edward Elric (Fullmetal Alchemist), Tanjiro Kamado (Demon Slayer) BOTW Link (Legend of Zelda)

Meta Knight MU tier list

The One: Riku (Kingdom Hearts)
Good Alts: Schezo Wegey (Puyo Puyo)
Meh: Zero (Mega Man)
No Thanks: Beta Ray Bill (Marvel)

What are your thoughts? Do you agree or disagree let me know in the comments below.