Suggestions by @dippy2

Oscar Isaac

as Ragman in Ragman

Christopher Nolan

as Director in Batman: The Dark Knight Returns

Brandon Routh

as CAMEO SUPERMAN in Batman: The Dark Knight Returns

Gary Oldman

as James Gordon in Batman: The Dark Knight Returns

Morgan Freeman

as Lucius Fox in Batman: The Dark Knight Returns

Ralph Fiennes

as Mister Freeze in Batman: The Dark Knight Returns

Michael Caine

as Alfred Pennyworth in Batman: The Dark Knight Returns

Joseph Gordon-Levitt

as Nightwing in Batman: The Dark Knight Returns

Christian Bale

as Batman in Batman: The Dark Knight Returns

Christian Bale

as Nightwing in Batman: The Dark Knight Returns

Don Cheadle

as Commander Steel in Superman 3

Don Cheadle

as Steel in Superman 2

Terrence Howard

as Henry Irons in Superman

Giancarlo Esposito

as Mr Freeze in Flash No Way Home

Jamie Foxx

as Two Face in Flash No Way Home

Alfred Molina

as The Penguin in Flash No Way Home

Willem Dafoe

as Joker in Flash No Way Home

Keanu Reeves

as The Caped Crusader Batman in Flash No Way Home

Brenton Thwaites

as Batman in Flash No Way Home

David Mazouz

as Red Robin in Flash No Way Home