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
The deck that did this most famously was Prosperous Bloom, refilling its mana and thinning its deck by combining Squandered Resources with Natural Balance or simply to boost its way to its first Cadaverous Bloom or Prosperity
the standard Legendary variant is only around $5 !
It generates three colors of mana, and it buffs your others just by being on the battlefield
WB lifegain decks appreciate the extra triggers, and its also a town for synergies, so ramp decks can stabilize early and get the payoffs later
As long as Snow Villiers is on the battlefield (and still a creature), that ability will count Snow Villiers itself