Since Ayula loads up on +1/+1 counters, you can power her up past what your opponents can handle, all while slapping on a few Mirran swords and hexproof auras to make sure your opponents cant interact with her at all
Chasm Skulker As you draw cards, Chasm Skulker gets massive
Delve is a sweet mechanic in general, and in spite of how dangerous I feel cards such as Treasure Cruise and Dig Through Time are in Eternal formats, at the very least theyre exciting dangerous cards, not annoying as hell ones like True-Name Nemesis
Broadside Bombardiersis banned in Historic
All these counters can also make it easy for the player's creatures to all have different power/toughness than each other, fueling coven more easily
And then somebody walks in with a large black bag