Godzilla x Kong's pink form was hinted in past Monsterverse films, evolving his atomic power. Tiamat's role in Godzilla: Dominion set up Godzilla's pink form fight in the graphic novel.
Abaddon (the giant spider), Behemoth (the giant wooly mammoth), Tiamat (a sea serpent), and the hilarious-looking “Doug.” Doug appears to look like something of a mix between Godzilla itself ...