how many ex cards are in a booster box Dream (M2a) MEGA Revavroom ex Pokemon TCG: XY Evolutions Sealed

Digimon Card Game - Booster Box - EX11 - Dawn Of Liberator

Every precedent that WotC has laid out shows that this is an arbitrary decision

Spreading out the different cards will indeed help the deck score more highly on traditional measures of randomness, since it increases the information-theoretic entropy of the deck

"Magic the Gathering TCG: Foundations Collector Booster Pack" is associated with the Magic the Gathering brand

The one that still sees play today is Squawkabilly ex, a core component of many turbo decks

Note that not all cards that create Bird tokens fall into this category, as its clear that while Hermes, Overseer of Elpis can create a small flock, those are just regular birds