Oops! All Spells is a pure combo deck that wins by milling its entire library with Balustrade Spy or Undercity Informer, then returning creatures from the graveyard to eventually cast Thassa's Oracle with an empty library. Your primary disruption is Thoughtseize, which you should fire off as early as possible to strip their key pieces like Dark Ritual, Cabal Ritual, or the mill payoff itself. Endurance and Faerie Macabre come in as graveyard hate — Faerie Macabre is especially valuable because it can be pitched for free at instant speed to exile Narcomoeba or Bridge from Below mid-combo, potentially breaking up their chain. Endurance is a resilient threat that can reset their graveyard if they've already started building it up, and it's tutorable via Green Sun's Zenith. Trim the expensive, slow finishers like Craterhoof, Atraxa, Icetill Explorer, and Quirion Ranger since this is a race against a turn-1 or turn-2 kill and those cards are irrelevant if you're not disrupting their combo in the first two turns.