Tessa Thompson as the first African-American (She's also part European and part Mexican) woman to play Brynhildr aka Valkyrie (Public domain Ancient Norwegian Mythology: She's often depicted as beach blonde, blue eyed, Caucasian and living in Norway. Richard Wagner wrote about her in his Der Ring des Nibelungen (The Ring of the Nibelung) German Opera series) and Chris Hemsworth as Thor (Another public domain Ancient Norwegian Mythological character).
Tessa Thompson as Brynhildr aka Valkyrie
Cate Blanchett as Hela (Based on a public domain Ancient Norwegian Mythology Goddess of the Underworld Hel)
Tom Hiddleston as Loki (Another public domain Ancient Norwegian Mythology Deity). You too can write your own Thor movie, book and/or musical/opera. Richard Wagner did it without getting sued by Disney (Of course, it helps that he died in 1883 (Forty years before Disney even got started)).
Jeff Goldblum as Grandmaster (Disney (Which purchased and owns Marvel Comics) exclusively owns the legal rights to this character)
Mark Ruffalo as Dr. David Bruce Banner aka the Hulk is stuck on the planet Sakaar with Thor (Who lost his magic hammer and now must fight evil without it). Those who provoke the Incredible Hulk---The vengeful temper tantrum throwing bright green Golem ends up learning an important lesson that they will never forget (Assuming they survive). Don't get him angry. You don't want to see him when he gets angry.
Chris Hemsworth as Thor