Why is the 'Dragon Ball' multiverse only comprised of 12 universes

Every universe in Dragon Ball, ranked from weakest to strongest

Dragon Ball Super only identifies episodes in S01 : r/PleX

I just realised the Universes that didn't participate in the tournament are both twin pairs : r/Dragonballsuper

Multiverse, Dragon Ball Wiki

Universe Zero AFTER Dragon Ball Super

How big is the Dragon Ball multiverse, both Canon and uncanon? - Quora

Why is the 'Dragon Ball' multiverse only comprised of 12 universes? - Quora

Why is the 'Dragon Ball' multiverse only comprised of 12 universes? - Quora

Why is the 'Dragon Ball' multiverse only comprised of 12 universes? - Quora

Does the multiverse exist in Dragon Ball? - Quora