Missing sideboard cards? The full 15-card sideboard runs about $110.
Buy sideboard on ManapoolOcelot Pride floods the board with Cat tokens and Amped Raptor/Thalia value creatures, so the extra Wrath of the Skies copies let you pay more energy to wipe their whole token board including Guide of Souls and Voice of Victory tokens. Lavinia taxes their noncreature removal and token-generating sorceries/instants while also countering any free spells, strong against a deck full of cheap disruption. Crucible of Worlds helps you fight through their Wasteland by recurring fetches and dual lands. Force of Negation is weaker here since their deck is creature-dense rather than noncreature-spell-dense, and Brainstorm is a lower priority against their proactive clock, so both come out for a more board-control-oriented plan.
Dimir Tempo runs a lot of cheap threats and plenty of Daze and Wasteland, so slow, mana-hungry cards like Wrath of the Skies and the sorcery-speed Prismatic Ending are low-impact here. Back to Basics is weak because it locks our own mana as well: most of our lands are nonbasic (fetches, duals, Karakas), so it hurts us at least as much as them. Consign to Memory is cheap interaction, but it only counters colorless spells and triggered abilities. Its colorless targets are Mishra's Bauble and Orcish Bowmasters' triggers, and it can't touch their colored spells like Moonshadow, Nethergoyf, or Bilbo. Rest in Peace shuts off Nethergoyf's escape, Nethergoyf and Barrowgoyf's graveyard growth, and Bilbo's casting from the graveyard, though Brazen Borrower or a counterspell can still answer it. Keep Force of Will and Force of Negation in to fight through Daze and their own Force of Will in the counter war.
Sultai Aluren wants to resolve Show and Tell, Aluren, or Omniscience and then cheat in Atraxa, Grand Unifier or Acererak the Archlich, so Pyroblast is excellent: for a single red mana it counters their blue key spells like Show and Tell, Atraxa, and Force of Will, and it can destroy a resolved Omniscience or Atraxa. It can't touch Aluren or Acererak, which aren't blue, so it is a supplement to our other answers rather than a catch-all. Lavinia, Azorius Renegade restricts their big noncreature spells like Show and Tell, Aluren, and Omniscience until they have enough lands, and counters anything they try to cast for free. Consign to Memory picks off their colorless spells and triggers. Back to Basics is cut because our own mana base is just as heavily nonbasic as theirs, and Prismatic Ending struggles to hit their big enchantments cheaply enough, so both come out; Gandalf trims to make room for the cheaper interaction.