Suggestions by @zenith2024

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

Spoiler

as "The Cyclops" in Titans B.C

King Ghidorah (Kingu Gidora)

as "The One Who Fell From The Stars" in Titans B.C

Spoiler

as "The One Who Fell From The Stars" in Titans B.C

Shiro Sagisu and Bear McCreary

as Composer in Destroy All Monsters: Final Wars

Aaron Taylor-Johnson

as Ford Brody in Destroy All Monsters: Final Wars

Millie Bobby Brown

as Madison Russell in Destroy All Monsters: Final Wars

Kaylee Hottle

as Jia in Destroy All Monsters: Final Wars