Suggestions by @seangrant

Anjelica Huston

as Lilandra in X-men (1978)

Lee Grant

as Lilandra in X-men (1978)

Gus Rethwisch

as Eric the red in X-men (1978)

Christopher Lloyd

as D’Ken in X-men (1978)

Gabriel Byrne

as Proteus in X-men (1978)

Liberace

as Arcade in X-men (1978)

Toshirō Mifune

as Silver samurai in X-men (1978)

Charlton Heston

as Victor creed in X-men (1978)

Roddy McDowall

as Bastion in X-men (1978)

Alexander Godunov

as Omega red in X-men (1978)

Rod Steiger

as Living monolith in X-men (1978)

John Candy

as Freddie dukes in X-men (1978)

Robert De Niro

as John proud star in X-men (1978)

Burt Reynolds

as Avalanche in X-men (1978)

Richard Roundtree

as Luke bishop in X-men (1978)

O. J. Simpson

as Luke bishop in X-men (1978)

Peter Cushing

as Charles Xavier in X-men (1978)

Ralph Richardson

as Charles Xavier in X-men (1978)

Peter O'Toole

as Charles Xavier in X-men (1978)

James Mason

as Charles Xavier in X-men (1978)