I have been following the Pokemon Metronome League on insta and got the Idea to try Something Like this myself, the only difference being that mine would be more Like the European Football system (mostly inspired by the english system) and this would be the First Design:

As far as I have looked Up there are 479 Pokemon that are their Evolution line's final evolution or dont have a Evolution Line that arent mythicals or legendaries. So I would seperate them into 6 Divisions with 80 each (79 in the 6th Division) and those into 4 groups. In the top Division (I'd call the Pokemon Metronome Premier League) the top 4 from each group advance to Championship Play-offs and the top 3 and bottom 3 of each dvision's groups being relegated/promoted (in the 6th Division No one would get relegated)

Each Season I would Draw the 4 groups of each Division again to keep it "fresh" and for the First Season I would Sort the Pokemon to each Division by BST (Base stat total).

Havent looked into stuff Like Abilities yet but I'd…