Suggestions by @liquidcarlton

Oingo Boingo

as Composer in MAH Hero Academ

James Cameron

as Director in MAH Hero Academ

Mike Myers (Full Cat in the Hat suit)

as Mirko in MAH Hero Academ

Haruhi Suzumiya

as Overhaul in MAH Hero Academ

Cinder Fall

as Cinder Fall in MAH Hero Academ

Paul McCartney

as Twice in MAH Hero Academ

Daniel J. D'Arby

as Darby in MAH Hero Academ

Smoker

as Kurogiri in MAH Hero Academ

Dawn of the Mummy

as Shigaraki in MAH Hero Academ

Jack Black (But with an Alvin and the chipmunks voice filter)

as All for one in MAH Hero Academ

Bill Murray (Space Jam)

as Lady Nagant in MAH Hero Academ

Finn Wolfhard

as Toga in MAH Hero Academ

Wayne Knight

as Stain in MAH Hero Academ

Conan O'Brien

as Mei Hatsume in MAH Hero Academ

Dave Bautista

as Endeavor in MAH Hero Academ

Jeff Goldblum & Lou Ferrigno

as Midnight in MAH Hero Academ

Alan Rickman

as Eraser Head in MAH Hero Academ

Toru (JoJo's Bizarre Adventure)

as Toru in MAH Hero Academ

Robin Williams

as Tokoyami in MAH Hero Academ

Tim Allen

as Hanta Sero in MAH Hero Academ