Suggestions by @danielnewman

Grey Damon

as Sam Scudder in The Flash

Travis Willingham

as William Dawson in The Flash

Greg Finley

as Leonard Snart in The Flash

Billy Magnussen

as Zoom in The flash:

Marco Grazzini

as Tar Pit in The flash:

Grey Damon

as Mirror Master in The flash:

Dan Payne

as King Shark in The flash:

Travis Willingham

as Grodd in The flash:

Robert Pattinson

as Godspeed in The flash:

Rita Wilson

as Nora allen in The flash:

Bruce Campbell

as Jay Garrick in The flash:

Roman Atwood

as The Trickster in The flash:

Michael Curiel

as Mick Rory in The flash:

Sam Worthington

as Leonard Snart in The flash:

Liam McIntyre

as George "Digger" Harkness in The flash:

Adam Rodriguez

as David Singh in The flash:

Shantel VanSanten

as Patty Spivot in The flash:

John Wesley Shipp

as Henry Allen in The flash:

Michael Rosenbaum

as Lex Luthor in The flash:

Danielle Panabaker

as Iris West in The flash: