Mainboard (60)
Creatures (3)
Instants (20)
Sorceries (13)
Artifacts (2)
Enchantments (4)
Dimir Tempo is your most challenging fair matchup — Thoughtseize strips your combo pieces while Wasteland attacks your blue sources, and Force of Will plus Daze protect their clock. Carpet of Flowers is exceptional here since they'll typically have multiple Islands in play, generating the mana needed to land Omniscience or Show and Tell through their disruption. Consign to Memory answers their post-board Force of Negation and can exile a Murktide Regent or Kaito token that threatens to end the game quickly. Cut Eureka (too slow and lets them put in Nethergoyf or Murktide for free), Lotus Petal (low impact when you need to go over multiple counterspells), and the one-ofs Planar Genesis and Sink into Stupor which are too situational. Your primary game plan is to resolve Show and Tell or Omniscience on turns 2-3 with Force of Will backup, ideally with Veil of Summer in hand to shut off their blue and black interaction simultaneously.
This is a mirror-style matchup where both decks are racing to resolve Show and Tell or their respective cheat effects, but Sneak and Show's Sneak Attack gives them a persistent threat engine that doesn't rely on sharing the battlefield. Your key advantage is that when you both put something into play off Show and Tell, Atraxa or Omniscience generates more immediate value than their Sneak Attack — prioritize putting Omniscience into play to take over the game. Flusterstorm and Consign to Memory come in to protect your combo from their Force of Will and Flusterstorm, and to counter their Sneak Attack activations. Surgical Extraction can remove Sneak Attack or Emrakul from their graveyard to weaken their redundancy. Eureka and Planar Genesis are trimmed as slower or narrower win conditions that are redundant given your four Show and Tells.
Oops, All Spells is a turbo-combo deck that wins on turn one or two by milling its entire library with Balustrade Spy or Undercity Informer and reanimating a Thassa's Oracle or using Dread Return for a lethal creature. This is a near-pure race where both decks are trying to combo faster than the other — Oops has little interaction in game one beyond Thoughtseize and Pact of Negation. Post-board, Grafdigger's Cage is your most powerful hate piece, shutting off Dread Return and Thassa's Oracle entirely; resolve it early off Ancient Tomb. Flusterstorm comes in to fight through their Pact of Negation when you're going off, and Surgical Extraction can exile a key piece like Thassa's Oracle if you see it in their graveyard after a disrupted attempt. Eureka and Sink into Stupor are trimmed as low-impact cards in this purely reactive-free race, and you should prioritize keeping fast Show and Tell lines protected by Force of Will and Veil of Summer.