>>54515722>>54515810There's no evidence of a Koraidon/Miraidon special Tera form, the terastal icon in the Pokedex could simply refer to the mascot of each part of the game (Scarlet/Violet -> Teal -> Indigo).
Terapagos on the other hand has two special forms according to datamining, its Terastal form and a new, unseen one (probably pic related)