Izzet Spellementals relies on graveyard-fueled discounts for Eddymurk Crab and Hearth Elemental, plus Flow State's upgraded two-card mode, so Rest in Peace exiling graveyards cripples both the cost reduction and their card selection. Torpor Orb shuts off the enter-the-battlefield triggers on Eddymurk Crab (tapping our creatures) and Sunderflock (bouncing our non-Elemental creatures), severely blunting their tempo swings; it does nothing against Hearth Elemental, which has no enter-the-battlefield trigger. Boomerang Basics and The Mind Stone are too slow against a deck that wants to race with cheap spells, so they come out for the proactive hate pieces. Keep the artifact engine (Simulacrum Synthesizer, United Battlefront) intact since it still outgrinds their spell-heavy game plan.