Hydroblast is excellent here, countering or destroying Fiery Temper, Lightning Bolt, Voldaren Epicure, Kessig Flamebreather, Guttersnipe, and any red permanent they commit. It can't touch Sneaky Snacker, which is blue-black rather than red. Expect Pyroblast and Red Elemental Blast out of their board, since our blue cards, Hydroblast included, are legal targets for them. Dust to Dust and Arms of Hadar aren't graveyard hate and do nothing to stop Sneaky Snacker from returning itself to the battlefield from the graveyard rather than being cast, so leave those at home. Trim small, fragile pieces like Baleful Strix and Black Mage's Rod's Hero token that trade poorly against a deck racing for direct damage, in favor of more interaction.

This is a grindy mirror-ish matchup where card advantage engines like Lorien Revealed, Brainstorm, and Spellstutter Sprite need to be disrupted; Envelop counters Lorien Revealed and other key sorceries. Pyroblast and Red Elemental Blast would be live against Counterspell, Dispel, Brainstorm, Spellstutter Sprite and Baleful Strix, but we lack room to bring them in without cutting core artifacts our Myr Enforcer and Thoughtcast need, so we leave them out this round. Steel Sabotage stays boarded since its only legal targets, Baleful Strix and Mukotai Ambusher, are too narrow to justify a slot. Trim a pair of our own Baleful Strix, since in a mirror-style grind they trade down rather than press an advantage.

Spy Combo wants to dump creatures into the graveyard (Balustrade Spy, Lotleth Giant via Dread Return) and ramp with Overgrown Battlement, Wall of Roots, and Saruli Caretaker. Arms of Hadar gives their whole team -2/-2 until end of turn, so it only picks off their small creatures: Elves of Deep Shadow, Quirion Ranger, Gatecreeper Vine, and Mesmeric Fiend. It will not kill Overgrown Battlement (0/4), Wall of Roots (0/5), Saruli Caretaker (0/3), Balustrade Spy (2/3), or Lotleth Giant (6/5), so treat it as a way to cut their early mana and disruption rather than a full sweeper. Our own lower-impact cards like Baleful Strix and a Blood Fountain matter less against a deck that isn't racing us on the stack, so we trim them for it. Keep the core artifact shell intact, since Myr Enforcer and Glint Hawk still apply pressure while they assemble their engine and Dispatch stays as cheap removal for a key creature.