Suggestions by @bosuthebluehedgehog

Keith David

as Anti-Monitor in Casting James Gunn's DCU! :D

Florian Munteanu

as B'wana Beast in Casting James Gunn's DCU! :D

Eva De Dominici

as Maxima in Casting James Gunn's DCU! :D

Elizabeth Debicki

as Big Barda in Casting James Gunn's DCU! :D

Isaiah Mustafa

as Martian Manhunter in Casting James Gunn's DCU! :D

Ewan McGregor

as Doctor Fate in Casting James Gunn's DCU! :D

Ron Perlman

as Solomon Grundy in Casting James Gunn's DCU! :D

Andy Samberg

as Mad Hatter in Casting James Gunn's DCU! :D

Brian Tyree Henry

as Steel in Casting James Gunn's DCU! :D

Andy Serkis

as Larfleeze in Casting James Gunn's DCU! :D

Sabrina Carpenter

as Wonder Girl in Casting James Gunn's DCU! :D

Taz Skylar

as Flash in Casting James Gunn's DCU! :D

Lucius Hoyos

as Kyle Rayner in Casting James Gunn's DCU! :D

Jason Isaacs

as Dan Garret in Casting James Gunn's DCU! :D

Kieran Culkin

as Mister Miracle in Casting James Gunn's DCU! :D

Jamie Campbell Bower

as Manchester Black in Casting James Gunn's DCU! :D

Malachi Barton

as Beast Boy in Casting James Gunn's DCU! :D

Emma Myers

as Tigress in Casting James Gunn's DCU! :D

Keegan-Michael Key

as Condiment King in Casting James Gunn's DCU! :D

Margaret Qualley

as Queen Mera in Casting James Gunn's DCU! :D