>>48562454Psychic used to be the most powerful type, with its supernatural portrayal at the time being above most of the others. I think even when this died out due to balancing mechanics, it sort of became unspoken "tradition" for a while, hence the Mew clones.
Dragons are just the stereotypical go to legendary creature in fiction, an obvious choice alongside Psychic. Even though we didn't technically have any "official" legends till Gen 3, Dragonite was often portrayed in the media as such and sometimes Lugia. Lugia is not a dragon type, but it's like a template for the later ones due to its design basis and often being equated to one.
I don't think Fairy has adequately replaced the above 2 just yet, but it's a solid contender.
