Suggestions by @marvelfanboy

Spoiler

as "The Kahndaq's savior" in Justice Society of America

James Mangold

as Director in Robin and The Batman

Kenneth Branagh

as Director in Aquaman: Throne of Atlantis

Michael James Shaw

as Black Manta in Aquaman: Throne of Atlantis

Kevin Bacon

as Deryl Frye in Birth of The Justice League

Elizabeth Lail

as Patty Spivot in The Flash: Born to Run

Kevin Bacon

as Darryl Frye in The Flash: Born to Run

Guillermo del Toro

as Director in Swamp Thing

James Mangold

as Director in Shadow of The Batman

Jamie Campbell Bower

as Scarecrow in Shadow of The Batman

Thomas Barbusca

as Jimmy Olsen in Birth of The Justice League

Daisy Ridley

as Iris West in Birth of The Justice League

Dave Bautista

as Killowog in Green Lantern: The Power of Will

Riley Keough

as Vicki Vale in Robin and The Batman

Christoph Waltz

as Mr. Freeze in Random Batman Fancast

Winston Duke

as Killer Croc in Random Batman Fancast

J. D. Pardo

as Bane in Random Batman Fancast

Tony Todd

as Clay Face in Random Batman Fancast

Mia Goth

as Harley Quinn in Random Batman Fancast

Millie Davis

as Batgirl in Random Batman Fancast