Mainboard (60)
Creatures (23)
Instants (10)
Sorceries (3)
Boros Energy is a wide, aggressive midrange deck that leverages Ocelot Pride and Ajani to flood the board with tokens while using Goblin Bombardment as a sacrifice outlet to punish sorcery-speed removal. Wrath of the Skies is your most important sideboard card here, cleanly resetting their board before they can convert creature advantage into lethal damage; prioritize sequencing it before they get Goblin Bombardment online. Celestial Purge provides efficient instant-speed answers to their most dangerous red permanents — Goblin Bombardment, Blood Moon, Phlage, and Ragavan are all live targets. Obsidian Charmaw enters as a large, cheap threat that punishes their nonbasic-heavy mana base and is particularly well-positioned when they are relying on Blood Moon to disrupt your lands. We trim Ephemerate and Consign to Memory since the blink synergy package is less critical in this interactive creature matchup, and shave Fable of the Mirror-Breaker and Casey Jones, Vigilante as the slowest cards that do not directly advance board parity.
The mirror is decided by who resolves their threats first and who can protect them — Ragavan and Phelia generate the most value, so counter magic becomes your most important tool post-board. Mystical Dispute, Force of Negation, and Strix Serenade come in to fight over key spells, particularly opposing Consign to Memory (which would exile your blinked creatures) and Teferi. Prismatic Ending and Galvanic Discharge are trimmed since neither player has many good targets — Ragavan and Phelia are the relevant creatures and neither dies cleanly to these. The Ephemerate-Phelia loop is the primary engine to protect; prioritize using Consign to Memory on opponent's Consign to Memory to keep your blink chain intact. Casey Jones provides an additional resilient threat that demands an answer, so keeping your curve full of pressure while holding up interaction is the key to winning the mirror.
Affinity is a fast artifact-based combo-aggro deck that wins through Kappa Cannoneer going wide with artifact tokens via Weapons Manufacturing, or by assembling Urza's Saga constructs backed by Mox Opal mana. Your primary plan is to leverage Solitude and Galvanic Discharge to pick off early threats, then close with Phlage and Ragavan before they reach critical mass. Wear/Tear is essential for hitting Mox Opal, Urza's Saga, or Shadowspear, while Celestial Purge cleanly exiles Kappa Cannoneer or Emry. Obsidian Charmaw comes in as a fast clock and to threaten their artifact lands like Fiery Islet and Spirebluff Canal. Teferi is slow against their proactive game plan and Wrath of the Skies is too expensive; shave one Prismatic Ending since Galvanic Discharge covers most of their small threats more efficiently.