Polymorph decks are based on getting rid of permanents from your field to turn them into permanents in your deck
While there are not a whole bunch of these types of spells, here are the few that I know of that can somewhat destroy (or rather make an opponent sacrifice) an enchantment: Aura Flux All other enchantments besides this one have a cost of 2 generic each upkeep If the 2 generic is not paid for an enchantment, it gets sacrificed (this also happens to your other enchantments too) Reality Acid An aura to place on a permanent Starts with 3 time counters it and one gets removed each upkeep Once all 3 are removed, the enchantment gets sacrificed Stealing Enchantments Truth be told, stealing an enchantment may be even better than destroying an enchantment
Unblocked attackers deal damage to your opponent, reducing your opponent's life points
Hare Raising is a Selesnya rabbits deck feature a nice suite of rares like Fecund Greenshell, Finneas, Ace Archer, and the deck exclusive Byrke, Long Ear of the Law
Maddening Cacophony Another card that seems designed to allow mill to keep up in the 4-player, 100-card world of Commander, Maddening Cacophony can get the majority of your opponents cards into the graveyard all by itself