There are currently a set of rules that add the validation for only pokemon in the regional dex of said Pokedex, with the available ones being gens 3-8.
So as the title entails, I am suggesting to add rules for the other gens as well as I don't see a reason why they don't exist beyond making the 3 separate Pokedexs for gen 9
And for gen 1 the rule could be split into "Old Kanto Pokedex" and "New Kanto Pokedex" similar to the Old and New versions of the Unova Pokedex with the new one adding melmetal and meltan
So as the title entails, I am suggesting to add rules for the other gens as well as I don't see a reason why they don't exist beyond making the 3 separate Pokedexs for gen 9
And for gen 1 the rule could be split into "Old Kanto Pokedex" and "New Kanto Pokedex" similar to the Old and New versions of the Unova Pokedex with the new one adding melmetal and meltan