When you are reliably finding one and winning with it when you just have three then you don't overly need a 4th
Search your library for a number of Plains cards equal to the difference, reveal those cards, put one of them onto the battlefield tapped and the rest into your hand, then shuffle
While this drop isnt fully available to the public yet, Black Lotus attendees in Atlanta have been able to pick it up early
Several Pokmon cards found in the upcoming expansion - not just the ex kind - enable players to obtain, move and expel energy cards to gain an advantage
The buyer still has to provide a card of the same rarity they either dont want or need, while the seller receives a card they can resell, repeating the process infinitely
Another notorious banned card introduced in this booster is Fiber Jar, a Flip Effect Monster that, when flipped, causes both players to shuffle all cards from their Field and Graveyard into their decks -- essentially resetting the duel, excluding banished cards