Suggestions by @harrybray

Flint Dille

as Writer in The Transformers: War of the Planets (1988)

Charlton Heston

as Primus in The Transformers: War of the Planets (1988)

David Harbour

as Captain Gutt in Ice Age (Live-Action)

Warren Beatty

as Iron man in Iron Man (1978)

Conrad Veidt

as The Joker in The Perfect DC Universe

Gene Hackman

as Doctor Octopus in 90s Spider-Man series

Christopher Walken

as Johnny in The Room (1973)

John Lydon

as The Joker in The Dark Knight (1988)

Sam Hamm

as Writer in Batman: Return of the Joker (1991)

James Earl Jones

as Steppenwolf in Zack Snyder's Justice League 90's

John Wood

as Tomar-Re in Zack Snyder's Justice League 90's

Angela Bassett

as Euboea in Zack Snyder's Justice League 90's

Elle Macpherson

as Menalippe in Zack Snyder's Justice League 90's

Patrick Stewart

as Ares in Zack Snyder's Justice League 90's

Alan Thicke

as Henry Allen in Zack Snyder's Justice League 90's

Peter O'Toole

as Yalan Gur in Zack Snyder's Justice League 90's

Sylvia Sidney

as Granny Goodness in Zack Snyder's Justice League 90's

Marc Alaimo

as Kilowog in Zack Snyder's Justice League 90's

Laura Serrano

as Artemis in Zack Snyder's Justice League 90's

Helena Bonham Carter

as Elizabeth Taylor in King of Pop (Season Five)