Suggestions by @ringothedrummer

Wyatt Russell

as Metallo in Superman: Birthright

Angela Bassett

as Martha Kent in Superman: Birthright

Forest Whitaker

as Jonathan Kent in Superman: Birthright

Zuleikha Robinson

as Lara in Superman: Birthright

Navid Negahban

as Jor-El in Superman: Birthright

Jake Gyllenhaal

as Lex Luthor in Superman: Birthright

Lupita Nyong'o

as Lois Lane in Superman: Birthright

Dev Patel

as Superman in Superman: Birthright

Sophie Aldred

as "An old friend" in Doctor Who (Season B)

Spoiler

as "An old friend" in Doctor Who (Season B)

Jason Isaacs

as The Master in Doctor Who (Season B)

Michael Sheen

as The Monk in Doctor Who (Season B)

Alex Kingston

as River Song in Doctor Who (Season B)

Nicholas Briggs

as Cybermen in Doctor Who (Season B)

Jonathan Watson

as Commander Tennak in Doctor Who (Season B)

John Leeson

as K-9 in Doctor Who (Season B)

Emma Thompson

as Professor Madeline Whittaker in Doctor Who (Season B)

Josh O'Connor

as Casey Davies in Doctor Who (Season B)

T'Nia Miller

as The Doctor in Doctor Who (Season B)

Jack Nicholson

as King Koopa in Super Mario Bros. (Second Draft)