Izzet Delver's red cards give Hydroblast plenty of live targets: it can counter Lightning Bolt, Unholy Heat or Cori-Steel Cutter, and it can destroy a resolved Dragon's Rage Channeler or Cori-Steel Cutter. It cannot touch their blue cards such as Murktide Regent, Daze, Force of Will or their own Hydroblast, so don't count on it for those. Consign to Memory counters their colorless Mishra's Bauble and answers triggered abilities such as the Flurry trigger from Cori-Steel Cutter or Dragon's Rage Channeler's surveil trigger. Kappa Cannoneer is a slow, expensive threat against a deck with Daze and Force of Will, so cut it and the Urza's Bauble copies for the much higher-impact color-hate package. Your Chalice of the Void at one also hits their one-mana cantrips and Lightning Bolt.