>>52777896The Regis and the mythical duo are great but I don't care for the rest of the legendaries, they don't look "organic" to me (the Regis actually fit with looking inorganic, not so much Groudon and it's hunched over posture or Rayquaza's overall "flat" look).
I'd say either gen 2 or gen 9. Ho-oh, Lugia, the beasts and Celebi all have perfect designs that's ornate, elegant, and looks alive in a way in which you can easily imagine how they'd move around. Gen 9 has the cursed objectmon legendaries which are great both in concept and execution with how bizarre and "off" they look as animals, and the lizard duo which are some of the best box legendaries we've ever had. If you count the paradoxmons, I like them all a lot too even if some of them are kind of boring/could be better.
