Izzet Delver's clock is built around Dragon's Rage Channeler and Murktide Regent, both colored creature spells, so Consign to Memory (which only counters colorless spells and triggered abilities) has few good targets here; cut it for Force of Negation, which can exile their noncreature spells like Cori-Steel Cutter, Lightning Bolt, and Flow State on their turn for free. It can't hit Dragon's Rage Channeler or Murktide Regent, since those are creature spells. Surgical Extraction is best once a copy of Murktide Regent or Dragon's Rage Channeler is in their graveyard: we can then exile every copy from their graveyard, hand, and library. Trim one Stifle to make room; it still has targets in their fetchlands, Wasteland, and Cori-Steel Cutter's flurry trigger, so we keep three. Keep Daze and Wasteland at full count to keep pace with their own tempo-disruption plan.