Suggestions by @boomstick2000

Daniel Dae Kim

as The Atom in Justice League: Darkseid War (1999)

Sean Connery

as Kent Nelson in Doctor Fate (1998)

John Lithgow

as Dr. Sivana in Shazam! (2000)

Arnold Vosloo

as Teth-Adam in Shazam! (2000)

Trevor Morgan

as Billy Batson in Shazam! (2000)

Brendan Fraser

as Shazam in Shazam! (2000)

Keith David

as John Henry Irons in Superman Lives (Part. 2) (1998)

Salma Hayek

as Hawkgirl in Justice League: Darkseid War (1999)

Tim Curry

as Sinestro in Green Lantern (1990)

Paul Rudd

as Kyle Rayner in Green Lantern 2 (1995)

Denzel Washington

as Jon Stewart in Green Lantern 2 (1995)

Leonardo DiCaprio

as The Flash in Justice League: Darkseid War (1999)

Val Kilmer

as Arthur Curry in Justice League: Darkseid War (1999)

Usher

as Aqualad in Teen Titans (1998)

Debi Mazar

as Killer Frost in The Flash 2 (1996)

Steve Buscemi

as Mirror Master in The Flash 2 (1996)

Bruce Campbell

as Captain Cold in The Flash 2 (1996)

Kevin Bacon

as Eobard Thawne in The Flash 2 (1996)

Jennifer Connelly

as Iris West in The Flash 2 (1996)

Jonathan Taylor Thomas

as Bart Allen in The Flash 2 (1996)