How to Get All Paradox Pokémon in 'Scarlet' and 'Violet'

There are plenty of Paradox Pokémon to catch in either version of the game, but there are a few things you’ll need to do first.

Namely, you can only encounter Paradox Pokémon after you’ve beaten the main story. During the post-game content, you’ll be able to enter the Great Crater of Paldea to explore.

Once there, it’s a simple matter of exploring until you find them spawning in. All of them can be find within the various biomes of Area Zero.

Source: https://www.distractify.com/p/how-to-get-all-paradox-pokemon-scarlet-violet