BRG is a creature-heavy midrange deck reliant on card advantage engines like The Sackville-Bagginses and Obsessive Pursuit, so Duress proactively strips their key spells before they resolve. Strategic Betrayal is a strong two-for-one against their best threats while also exiling their graveyard to shut off Lively Dirge's recursion. Together as One is too slow and mana-inefficient against an aggressive curve-out deck, and Nowhere to Run's -3/-3 whiffs on many of their bigger threats once pumped, so both get cut for proactive answers.

Izzet Spellementals is largely blue and red spells, so Flashfreeze is a premium answer to their red spells like Prismari Charm and Hearth Elemental. Disdainful Stroke catches their bigger payoffs like Eddymurk Crab or Traumatic Critique, while Annul can stop their Ghost Vacuum artifacts, though it is mostly a sideboard trim; keep it minimal. Nowhere to Run's -3/-3 doesn't kill their 5-toughness Hearth Elemental, and Shoot the Sheriff is redundant with our sweepers against their creature shell. Prioritize proactive countermagic to stop their engine before it snowballs, since this is a race against incremental card advantage.

Flashfreeze is excellent here since Izzet Spellementals leans heavily on red spells, hitting Hearth Elemental and Prismari Charm at a full tempo discount, though it whiffs on their mono-blue cantrips and on Sunderflock. Disdainful Stroke picks off Eddymurk Crab, Sunderflock, and Traumatic Critique cast for X=4 or more. Nowhere to Run's -3/-3 is often too small against Hearth Elemental's sturdy 4/5 body and doesn't stop the cantrip chain, so it comes out in favor of proactive countermagic. Together as One is clunky against a deck that wants to race with cheap spells and empties its hand quickly, making it a low-impact late draw here.