While this technically makes a four-card combo , the requirements are easy to meet by the time Crackdown Construct enters
Lightning, Army of One Rarity: Mythic Rare TYPE: Legendary Creature SUBTYPE: Human Soldier CMC: 3 Mana cost: USD: $23.03 EUR: 18.80 TIX: 0.14 EDHREC RANK: 2663 (3/2) First strike, trample, lifelink Stagger Whenever Lightning deals combat damage to a player, until your next turn, if a source would deal damage to that player or a permanent that player controls, it deals double that damage instead
They also count spells cast from outside the game, such as spells cast with Wish or Garth One-Eye's ability
Savvy players just snipe the Instructor first before wiping the board anyway
Xenosquirrels uses its +1/+1 counters to tweak dice rolls in your favor
Ive already mentioned ICRs as secondary perks for some other card-earning methods, but its a definite path on its own, too