Suggestions by @mclovin

Ben Mendelsohn

as Talos in What if...?

Taika Waititi

as Korg in What if...?

Karl Urban

as Skurge in What if...?

Jeff Goldblum

as En Dwi Ghast in What if...?

Tessa Thompson

as Brunilda in What if...?

Elizabeth Debicki

as Ayesha in What if...?

Bradley Cooper

as Rocket Raccoon in What if...?

Colm Feore

as Laufey in What if...?

Anthony Hopkins

as Odin in What if...?

Idris Elba

as Heimdall in What if...?

Ray Stevenson

as Volstagg in What if...?

Zachary Levi

as Fandral in What if...?

Tadanobu Asano

as Hogun in What if...?

Rene Russo

as Frigga in What if...?

Cobie Smulders

as Maria Hill in What if...?

Kat Dennings

as Darcy Lewis in What if...?

Natalie Portman

as Jane Foster in What if...?

Angourie Rice

as Betty Brandt in What if...?

Toni Revolori

as Flash Thompson in What if...?

Zendaya

as Michelle Jones in What if...?