Mainboard (60)
Creatures (20)
Instants (8)
Sorceries (1)
Enchantments (8)
Planeswalkers (1)
Boros Energy goes wide with small creatures—Guide of Souls, Ocelot Pride, and cat tokens are all x/1s that die to Rough/Tumble, which is your most impactful sideboard card here. Wrath of the Skies sweeps any flying threats and residual boards they rebuild with. Wear/Tear answers Goblin Bombardment (their sacrifice-based reach), Elegant Parlor, and any active Arena of Glory. Consign to Memory and Stubborn Denial are dead weight against a non-blue deck leaning on low-to-the-ground creatures rather than haymaker spells. Your Ragavan, Scion of Draco, and Leyline Binding package already give you a strong proactive and interactive game plan; the sideboard slots simply replace reactive counterspells with sweepers and permanent removal that actually pressure their board state.
This is a midrange mirror where they out-grind you with Solitude, Ephemerate value loops on Casey Jones and Phelia, and Quantum Riddler card advantage — you need to be the aggressor and disrupt their engine rather than fight on their terms. Doorkeeper Thrull is quietly one of your best cards here: it forces them off Solitude as an answer to your threats, making Territorial Kavu and Phlage much harder to answer cleanly. Mystical Dispute is premium, countering Solitude, Consign to Memory, and Quantum Riddler for a single blue mana, and the additional Consign to Memory copies give you further protection for your key spells and threats. Stubborn Denial is trimmed because their threats — Phlage, Casey Jones, Quantum Riddler — are large enough to make ferocious unreliable before you've established a board, and the Dispute/Consign package is simply better interaction in this matchup. Prioritize landing Scion of Draco or Phlage early to apply clock pressure; if they're tapping out for Ephemerate loops you can punish them without needing to fight over every resource.
Affinity is a fast artifact-based combo deck that wins through Kappa Cannoneer and Weapons Manufacturing generating overwhelming board presence backed by Urza's Saga. Wear/Tear is essential for destroying Mox Opal, Urza's Saga tokens, and the Saga itself before it finds key pieces. Rough/Tumble cleans up wide boards of artifact creatures and Construct tokens that would otherwise race past your defenses, since sweeping at flying level handles most of their threats cleanly. Path to Exile handles a resolved Kappa Cannoneer that has gotten too large to kill otherwise. Consign to Memory and Stubborn Denial come out because Affinity runs very low to the ground and resolves most threats quickly; their counterspells are defensive tools better suited against spell-based decks, and Teferi is too slow when they can goldfish a win through multiple angles.