Mime's Shiny form now released, Goomy is the only one among them that cannot be encountered in its Shiny form in Pokémon GO as of yet.
These are the Pokémon that will appear in Tier Five raids in Pokémon GO this December 2022:
December 1st – December 8th, 2022: Virizion
December 8th – December 15th, 2022: Terrakion
December 15th – December[...]