Suggestions by @zenith2024

Gaite Jansen

as Janet Van Dyne in Ant-Man and The Wasp (2009)

Chris Geere

as Hank Pym in Ant-Man and The Wasp (2009)

Jeremy Irons

as Magneto in X-Men: First Class (2008)

Kelsey Grammer

as Beast in X-Men: First Class (2008)

Brenton Thwaites

as Cyclops in X-Men: First Class (2008)

Anguirus (Angirasu)

as Anguirus in Titans B.C

Minilla

as Minilla in Titans B.C

Godzilla (Monsterverse)

as Hound in Titans B.C

Skar King

as Kjartan in Titans B.C

The Kongs

as Kjartan's Army in Titans B.C

Shimo (MonsterVerse)

as Shimo in Titans B.C

Methuselah

as Methuselah in Titans B.C

Godzilla (Monsterverse)

as Kaminari in Titans B.C

Godzilla (Monsterverse)

as Raijin in Titans B.C

Battra

as Battra in Titans B.C

Godzilla (species)

as Other Gojiras in Titans B.C

Dagon

as Dagon in Titans B.C

Rodan (MonsterVerse)

as Rodan in Titans B.C

Mothra (MonsterVerse)

as Mothra in Titans B.C

Gigan

as "The Cyclops" in Titans B.C