Suggestions by @benjombunud

Guy Pearce

as Thaddeus Thawne in The Flash: Scarlet Speedster

James Arnold Taylor

as Ch’p in Green Lantern Corps: The Power Of Will

Ewan McGregor

as Tomar-Re in Green Lantern Corps: The Power Of Will

Jessica Alba

as Carol Ferris in Green Lantern Corps: The Power Of Will

Alan Ritchson

as Guy Gardner in Green Lantern Corps: The Power Of Will

Jake T. Austin

as Kyle Rayner in Green Lantern Corps: The Power Of Will

Jensen Ackles

as Hal Jordan in Green Lantern Corps: The Power Of Will

Jerry O'Connell

as Henry Allen (Young) in The Flash: Scarlet Speedster

An Unknown Actor

as Young Eobard Thawne in The Flash: Scarlet Speedster

An Unknown Child Actor

as Barry Allen (Kid) in The Flash: Scarlet Speedster

Rachel McAdams

as Nora Allen in The Flash: Scarlet Speedster

Ted Danson

as Darryl Frye in The Flash: Scarlet Speedster

Hiroyuki Sanada

as Valve in Generator Rex

Charlize Theron

as Black Knight in Generator Rex

Jensen Ackles

as “A Friend” in The Flash: Scarlet Speedster

Spoiler

as “A Friend” in The Flash: Scarlet Speedster

Wyatt Russell

as Captain Cold in The Flash: Scarlet Speedster

Antony Starr

as Reverse Flash in The Flash: Scarlet Speedster

Miles Brown

as Wally West in The Flash: Scarlet Speedster

Dennis Quaid

as Henry Allen in The Flash: Scarlet Speedster