Mainboard (60)
Creatures (36)
Instants (5)
Sorceries (3)
Boros Energy is a fast, wide aggro deck that generates significant value through Ocelot Pride tokens, Guide of Souls counters, and Ajani, Nacatl Pariah triggers, so your priority is disrupting their board state before it snowballs. Culling Ritual is exceptional here, sweeping their token-heavy boards while generating mana that can fuel the rest of your turn. Mystical Dispute comes in as cheap interaction against Phlage, Seasoned Pyromancer, and Ranger-Captain of Eos since the opponent will frequently be tapping out on their turn. Force of Vigor handles Goblin Bombardment and any Blood Moon they bring in from the sideboard, both of which can be backbreaking. Force of Negation and Sink into Stupor come out because the opponent is primarily a creature-based threat that requires permanent removal rather than permission, and Fblthp is too slow to have meaningful impact at their aggressive pace.
Jeskai Blink generates sustained value through Ragavan, Phelia blink loops, and Phlage while disrupting your game plan with Consign to Memory and Galvanic Discharge. Harbinger of the Seas is your most powerful tool here — it converts all their non-Island lands to Islands on entry, effectively cutting off their white and red mana sources and stranding Phlage, Solitude, and their removal spells. Post-board, you increase counterspell density with Mystical Dispute and Consign to Memory to fight over their free spells and card-advantage threats; Mystical Dispute in particular answers Quantum Riddler, their own Consign to Memory, and Solitude cheaply. Endurance is trimmed as they have minimal graveyard reliance beyond a single Phlage escape trigger, and Fblthp and two copies of Birthing Ritual come out as the lowest-impact cards in a matchup that rewards dense interaction and tempo.
Affinity is a fast artifact-based combo deck that threatens to win quickly through Kappa Cannoneer, Urza's Saga tokens, and Weapons Manufacturing going wide. Collector Ouphe is your most important sideboard card, shutting off Mox Opal, Engineered Explosives, and Aether Spellbomb while being pitch-able to Subtlety if needed. Culling Ritual is a devastating sorcery-speed sweeper that can wipe their board of low-cost artifacts and small creatures while generating enough mana to net positive or follow up immediately. Force of Vigor provides free permanent removal, hitting Urza's Saga, Mox Opal, or Engineered Explosives at no mana cost. Force of Negation comes out because the opponent is primarily a non-spell threat deck where their most dangerous plays are permanent-based, and Harbinger of the Seas has minimal impact since Affinity runs very few basic lands.