Sneak and Show wants to cheat Emrakul, the Aeons Torn or Atraxa, Grand Unifier into play via Sneak Attack or Show and Tell, both of which put creatures onto the battlefield without casting them. Lavinia, Azorius Renegade is excellent since it counters any spell they cast without paying mana (like Force of Will) and prevents them from casting noncreature spells with mana value greater than the number of lands they control, stopping early Show and Tell or Sneak Attack cast off fast mana. Deafening Silence limits them to one noncreature spell a turn, which is brutal against a deck whose entire gameplan is a single enchantment or sorcery. Consign to Memory counters triggered abilities like Atraxa's enter-the-battlefield trigger and hits colorless spells like Lotus Petal. Stifle is too narrow here and Force of Negation is redundant with the more proactive hate pieces coming in.