Suggestions by @avp_goat

Ian McShane

as Alfred Pennyworth in Nightwing

Pedro Pascal

as Deathstroke in Nightwing

Derek Mears

as Blockbuster in Nightwing

Oliver Jackson-Cohen

as Batman in Nightwing

Kiera Allen

as Oracle in Nightwing

Sebastian Amoruso

as Nightwing in Nightwing

Oliver Jackson-Cohen

as "The Bat" in Plastic Man

Spoiler

as "The Bat" in Plastic Man

Mackenzie Davis

as Magpie in Plastic Man

Rafael Casal

as Kite Man in Plastic Man

Adam Copeland

as Sportsmaster in Plastic Man

Flula Borg

as Animal-Vegetable-Mineral Man in Plastic Man

Matthew Lillard

as Condiment King in Plastic Man

Sam Witwer

as Onomatopoeia in Plastic Man

Dan Fogler

as The Calculator in Plastic Man

Harvey Guillén

as Woozy Winks in Plastic Man

Mary Elizabeth Winstead

as Agent Morgan in Plastic Man

Albert Brooks

as Chief Branner in Plastic Man

Freddie Stroma

as Plastic Man in Plastic Man

Raymond Cruz

as General Lane in SUPERMAN: UP IN THE SKY