Suggestions by @robertwaynecarroll

Jared Leto

as The Joker (Opening Scene Cameo) in The Flash

Dwayne Johnson

as Black Adam (Teth-Adam) (Opening Scene Cameo) in The Flash

David Mazouz

as Robin (Damian Wayne) (Cameo) (Nolanverse) in The Flash

LaMonica Garrett

as The Monitor (Mar Novu) (Post-Credits Scene) in The Flash

Tony Todd

as Anti-Monitor (Post-Credits Scene) in The Flash

John Cena

as Shazam (Billy Batson) (End Of Movie Cameo) in The Flash

Idris Elba

as Green Lantern (John Stewart) (Cameo) (Campbellverse) in The Flash

Chris Cooper

as The Hobgoblin (Norman Osborn) in The Amazing Spider-Man 4

Zachary Levi & Jack Dylan Grazer

as Captain Thunder (Freddy Freeman) (Flashpoint Earth) in The Flash

Charlie Plummer

as Nightwing (Dexter dent) (Flashpoint Earth) in The Flash

Gal Gadot

as Wonder Woman (Diana Prince) (Flashpoint Earth) in The Flash

David Ramsey

as Green Lantern (John Diggle) (Cameo) (Arrowverse) in The Flash

Taylor Swift

as Supergirl(Kara Zor-El) (Linda Lee Danvers) (Mid-Credits Scene) (Lands on earth) in The Flash

Antje Traue

as Faora-Ul (Flashpoint Earth) in The Flash

Patrick Wilson

as Ocean Master (Orm Marius) (Flashpoint Earth) in The Flash

Grant Gustin

as Flash (Barry Allen) (Cameo) (Arrowverse) in The Flash

Zachary Levi and Asher Angel

as Shazam (Billy Batson) (Opening Scene Cameo) in The Flash

Christian Bale

as BATMAN (Bruce Wayne) (Cameo) (Nolanverse) in The Flash

Ryan Reynolds

as Green Lantern Hal Jordan (Cameo) (Campbellverse) in The Flash

Margot Robbie

as Yo-Yo (Harleen Quinzel) (Flashpoint Earth) in The Flash