Izzet Prowess aims to close the game quickly with Monastery Swiftspear and Dragon's Rage Channeler backed by cheap pump spells, so Brotherhood's End is your most impactful sideboard card — it sweeps their entire board of 1-toughness creatures at instant speed. Endurance comes in as a flash blocker with reach that also disrupts Dragon's Rage Channeler's delirium count, buying critical time to land Crashing Footfalls and stabilize. Mystical Dispute replaces Force of Negation as the more mana-efficient counter in this matchup, stopping Preordain, Expressive Iteration, and post-board Consign to Memory for a single blue mana. Force of Negation and Subtlety are trimmed because Force of Negation is weak against their low-to-the-ground noncreature spells and Subtlety's tempo bounce is insufficient against the volume of cheap threats they deploy. Your Leyline of the Guildpact and Leyline Binding package remains the backbone of your game plan, as protection from monocolored shuts off Lightning Bolt and Lava Dart targeting your Rhino tokens.

Affinity is a fast artifact-based deck that wins through Kappa Cannoneer and Pinnacle Emissary backed by Mox Opal acceleration and Urza's Saga constructs — your primary goal is to land a Crashing Footfalls cascade before they can establish a board you can't race. Force of Vigor is your highest-impact sideboard card, destroying key artifacts like Mox Opal, Engineered Explosives, and Urza's Saga for free at instant speed. Brotherhood's End wipes the small-creature and Saga-token side of their board while leaving your rhinos intact. Mystical Dispute replaces Force of Negation as the more mana-efficient counter against their blue interaction (Metallic Rebuke, post-board Consign to Memory, Kappa Cannoneer), costing just one blue mana against those targets. Blood Moon punishes their greedy non-basic land base — they have only a single Island as a basic, so it effectively cuts them off colored spells while your fetch-heavy manabase handles the lock with ease; Subtlety and Fire/Ice come out because bouncing artifacts is too temporary and pinging is too low-impact against a deck that presents 4/4s and ward-protected finishers.

This is a mirror-adjacent matchup where both decks share core infrastructure — Leyline of the Guildpact, Scion of Draco, and Leyline Binding — but Domain Zoo disrupts your cascade plan primarily through Consign to Memory and Stubborn Denial (which becomes a hard counter with Ferocious from their large creatures). Mystical Dispute comes in as a one-mana answer to their counterspells and their own blue threats like Subtlety, making it the highest-impact sideboard card here. Tishana's Tidebinder adds a body and can counter Ragavan's triggered ability or Phelia's ETB, stranding their tempo plays. Fire/Ice is the cleanest cut: Ice tapping Ragavan is marginally useful, but Fire dealing 2 damage rarely kills anything relevant when Territorial Kavu and Quantum Riddler dominate their threat base. Prioritize resolving Crashing Footfalls on their end step and keep Force of Negation up to counter Consign to Memory.