Death and Taxes (Yorion) is your most challenging non-combo matchup — Thalia, Guardian of Thraben makes every noncreature spell cost 1 more, Disruptor Flute (which they run 4 of maindeck) names Show and Tell or Sneak Attack, White Orchid Phantom and Field of Ruin destroy your non-basic lands, and Karakas bounces any legendary creature you sneak into play including Atraxa. The critical play pattern is to use Sneak Attack with Emrakul, the Aeons Torn since Emrakul is not legendary and cannot be Karakas'd, and its annihilator 6 trigger forces them to sacrifice their entire board on the attack. Abrade destroys Disruptor Flute, Aether Vial, or Stoneforge Mystic before she finds an equipment, while Magus of the Moon shuts off their Field of Ruin, Ghost Quarter, Karakas, and Wasteland since all their lands are non-basic. Post-board Deafening Silence and Containment Priest are severe problems — Silence stops sorcery-speed Show and Tell and Sneak Attack activations, so prioritize finding Force of Will to answer these before attempting the combo. Hexing Squelcher provides an additional threat body and its Bolt mode handles Thalia cleanly.