Suggestions by @marvelfanboy

Spoiler

as "He is not from that world" in The Authority

Jonathan Groff

as Apollo in The Authority

Luke Evans

as Midnighter in The Authority

Alex Garland

as Director in The Authority

Robert De Niro

as Quentin Lance in Green Arrow & Black Canary

Mary J. Blige

as Amanda Waller in Green Arrow & Black Canary

Maya Hawke

as Thea Queen in Green Arrow & Black Canary

Jamie Lee Curtis

as Moira Queen in Green Arrow & Black Canary

Michael Jai White

as John Diggle in Green Arrow & Black Canary

Asher Angel

as Roy Harper in Green Arrow & Black Canary

Jon Bernthal

as Wildcat in Green Arrow & Black Canary

Brian Tee

as Dark Archer in Green Arrow & Black Canary

Rian Johnson

as Director in Green Arrow & Black Canary

David Tennant

as Onomatopeia in Green Arrow & Black Canary

Gerard Butler

as Deathstroke in Green Arrow & Black Canary

Vanessa Kirby

as Black Canary in Green Arrow & Black Canary

Billy Magnussen

as Green Arrow in Green Arrow & Black Canary

James McAvoy

as "Hi plant guy" in Swamp Thing

John Constantine

as "Hi plant guy" in Swamp Thing

Spoiler

as "Hi plant guy" in Swamp Thing