Golgari Midrange has plenty of cheap permanents that Abrupt Decay answers cleanly, such as Badgermole Cub, Sentinel of the Nameless City, and Unholy Annex with only its front half unlocked. Decay can't be countered. It only hits mana value 3 or less, so it can't touch Professor Dellian Fel or Sheoldred, the Apocalypse (both mana value 4). Save it for their early plays and don't count on it against their top end. Duress backs up our Thoughtseize to strip noncreature, nonland cards such as their removal (Fatal Push, Abrupt Decay, Go for the Throat) and Professor Dellian Fel before they can use them on our key pieces. Torch the Tower struggles against Sheoldred's 5 toughness and Badgermole Cub's earthbent lands, and The Sackville-Bagginses trades down against their efficient removal suite (Fatal Push, Abrupt Decay, Go for the Throat). Keep Oni-Cult Anvil and Deadly Dispute as the primary grindy engine against their midrange plan.

Izzet Cauldron relies on counterspells like Stubborn Denial and Get Out plus Prismari Charm bounce; Hexing Squelcher makes our spells uncounterable and gives our team Ward against their removal. Soul-Guide Lantern slows down Eddymurk Crab's cost reduction (fewer cards in their graveyard) and denies Hearth Elemental's Adventure discard synergy with graveyard cards. Thoughtseize is weak since they're a low-curve tempo deck with few must-strip cards early, and Torch the Tower is awkward against their 5/5s and 4/5s. Keep the sacrifice/artifact engine intact since they have no efficient artifact removal besides Abrade in the sideboard.

Selesnya Company presents cheap, high-value permanents (Skyclave Apparition, Archon of Emeria, Thalia, Guardian of Thraben) that Abrupt Decay removes outright at mana value 3 or less, bypassing their lack of counterspells. Duress strips removal like Get Lost before it can hit our key engine pieces. Torch the Tower is undersized against Badgermole Cub's earthbent land threat and most of their bigger bodies, and our own Thoughtseize is risky against Archon of Emeria's one-spell-per-turn restriction which can strand it in hand. Prioritize removing Archon of Emeria and Thalia early since both tax our spell-heavy engine significantly.