Izzet Delver is heavily blue with Force of Will, Daze, Brainstorm, and Ponder, so Pyroblast is a premium answer, able to counter their protection spells or destroy a resolved Murktide Regent. Chrome Mox is risky against their Wasteland and card-advantage engines, exposing information for little benefit, so trim it for reactive power. The extra Eldrazi Confluence adds a flexible answer that can shrink a Dragon's Rage Channeler or Murktide Regent via the +3/-3 mode. Keep Trinisphere and Chalice of the Void mainboard, since they are excellent against their one-mana cantrip suite and Lightning Bolt.