Suggestions by @johnhomer

Jensen Ackles

as Green Lantern in Justice League: Legion of Doom

Score: +1

Dan Stevens

as Flash in Justice League: Legion of Doom

Score: +1

Bridget Regan

as Wonder Woman in Justice League: Legion of Doom

Score: +1

Jon Hamm

as Batman in Justice League: Legion of Doom

Score: +1

Matt Bomer

as Superman in Justice League: Legion of Doom

Score: +1

Daisy Ridley

as Killer Frost in The Flash

Score: +1

Liam Hemsworth

as Captain Boomerang in The Flash

Score: +1

Rhys Ifans

as Henry Allen in The Flash

Score: +1

Tessa Thompson

as Iris West in The Flash

Score: +1

James Earl Jones

as Gorilla Grodd in The Flash

Score: +1

Michael C. Hall

as Captain Cold in The Flash

Score: +1

Matthew McConaughey

as The Reverse Flash in The Flash

Score: +1

Thomas Barbusca

as Impulse in The Flash

Score: +1

Tom Hanks

as The Original Flash in The Flash

Score: +2

Cameron Monaghan

as Flash II/Kid Flash in The Flash

Score: +1

Dan Stevens

as The Flash in The Flash

Score: +1

Jason Momoa

as Vandal Savage in Titans/Young(er) Justice

Score: +1

David Warner

as Doctor Midnite I in Justice Society of America

Score: +1

Mena Massoud

as Doctor Fate II in Justice Society of America

Score: +1

Ian McKellen

as Doctor Fate I in Justice Society of America

Score: +1