Its crucial to their game plan
Today we'll have three Honorable Mentions and then 10 cards to be a Top Thirteen overall, and then I may not come back since I am out for two weeks at Israel vacationing with my family and I wrote this article last week before I left, but I copied over every card into my master list in case we are still in an Unfinity mood later
However, you can consider playing fewer than four copies of a card if: It gets worse in multiples (such as legendary creatures) It's only useful against certain matchups It's a win condition, and your control deck will have time to dig through the deck and find it You're stuck choosing between two cards which have equally strong, similar, but slightly different effects (you could play two of each) It's a slightly worse version of a card you have four copies of already, and you're including it because you want even more of that effect
This list focuses on cards that can put counters on themselves and others, with a bias towards Commander and Cube, though all-stars in other formats can show up
These numbers will be accurate if you open enough packs