Izzet Spellementals relies on cheap red and blue spells like Opt, Sleight of Hand, Flow State, and Prismari Charm to fuel its Hearth Elemental and Eddymurk Crab, so Flashfreeze is a clean counter against their many red spells (Burst Lightning, Prismari Charm, Traumatic Critique, Impractical Joke). Negate covers the noncreature spells that Flashfreeze can't touch because they aren't red or green, such as the blue Opt, Sleight of Hand, Flow State, and Get Out, and it also hits Traumatic Critique and Prismari Charm. Requiting Hex and Witherbloom Charm's cheap removal stay in the board since their key threats are mana value 6+ on the battlefield; trim Rapid Rescue and Awaken the Honored Dead for the extra interaction since this matchup is about disrupting their spell chain before it snowballs.