Missing sideboard cards? The full 15-card sideboard runs about $235.
Buy sideboard on ManapoolDimir Tempo brings heavy free countermagic in Force of Will and Daze plus Wasteland, so redundant, resilient angles matter more than raw payoff. Empty the Warrens is a Storm sorcery that can close the game with a swarm of Goblin tokens even if our primary kill spell gets countered or discarded, giving us a second attack angle they must respect. Galvanic Relay is a Storm sorcery that generates card advantage even at low storm count, helping rebuild after a Thoughtseize strips our hand or a countered spell sets us back. We shave the second Tendrils of Agony copy since one is redundant as a kill spell, and Song of Creation is risky against their proactive disruption suite since discarding our hand each end step is dangerous if we're not closing that turn.
Eldrazi's Chalice of the Void is the biggest threat to our plan since it can lock out Dark Ritual, Lotus Petal, or Brainstorm depending on the count they set; Thoughtseize lets us proactively strip a Chalice or a Thought-Knot Seer before it locks us out. Pulverize can sacrifice two Mountains to destroy all artifacts, wiping their Chalice of the Void and Lotus Petals in one shot, which is worth the slight awkwardness of needing two Mountain-type sources. We trim one Chrome Mox since imprinting away a card is risky against their discard-adjacent Thought-Knot Seer taxing our hand, and a Badlands since our red/black fixing is otherwise sufficient. Play around Chalice for zero and one especially, sequencing rituals before cantrips when possible.
Ocelot Pride Midrange leans on Wasteland and Karakas to disrupt our nonbasic-heavy manabase, so the two copies of Boseiju, Who Endures give us a land while doubling as removal for a Karakas or an artifact like a stray Chalice effect via its channel ability. Thoughtseize adds proactive disruption to strip Thalia, Guardian of Thraben or a key Voice of Victory before they can stop our combo. We are not touching our combo core; this is a light land-quality upgrade plus one disruption spell. Watch for Pyroblast countering our blue cantrips, so sequence Brainstorm and other draw spells carefully.