Humans because there are simply so many of them, especially in white, where you can run multiple Champion of the Parish without watering down the card quality in the rest of the color
That means you wont find filler commons here, only the cards that truly matter in Commander, cEDH, Legacy, Vintage, and Cube
At higher rarities, we designed cards that required you to have a high density
Decks vary how many copies they play based on how reliably they want to have a copy once they hit seven mana, which is usually a question of how often they need that boost to win the game combined with how much they need to sacrifice to make sure they get that far
At the beginning of your upkeep, you lose 1 life for each burden counter on The One Ring