I haven't looked at the disassembly for the TCG game like I have for Crystal and Emerald, but all the attention and interest hacking this has gotten in the last year has me hopeful
Commander, Modern, Standard, Legacy, Vintage, Pioneer, Pauper, Brawl, Oathbreaker, or casual
Immediately after this effect resolves, Xyz Summon 1 "Utopia" or "Utopic" Xyz Monster using only those 3 monsters
Honorable Mention: Long-Range Sensor In any deck where you want to attack every player every turn, it is super easy to get almost free spells by Discovering 4 for just one mana
This implied that a player might launch some serious attacks on turn one if they could stack their deck with 4 Black Lotus and were fortunate with the draw
However, if you're trying to build a deck for the first season of ranked battles, and only need one more copy of a key card, you should grab the Starter Deck that contains the last card that you need