Izzet Delver leans on free countermagic (Daze, Force of Will) and cheap cantrips to grow Dragon's Rage Channeler and Murktide Regent, so Consign to Memory is strong against their colorless Mishra's Bauble and their triggered abilities (Dragon's Rage Channeler surveil, Cori-Steel Cutter flurry, Murktide Regent counters) while being cheap to cast. Dismember cleanly answers an early Dragon's Rage Channeler or a smaller Murktide Regent for as little as 1 mana plus life, which matters since you want to kill their threats before they grow out of range. Trim the narrow situational one-ofs that don't interact meaningfully with their aggressive clock. Chalice of the Void mainboard remains excellent, punishing their extensive 1-mana suite (Brainstorm, Ponder, Lightning Bolt, Dragon's Rage Channeler) when set to 1.