Torpor Orb is very strong here, shutting off the enter-the-battlefield triggers that drive this blink deck: Flickerwisp, Witch Enchanter, Orcish Bowmasters, and Solitude all lose their enter-the-battlefield effects, which also blanks evoked Solitude and turns Ephemerate into a much weaker play. It does not stop Phelia, Exuberant Shepherd, whose ability triggers when it attacks, and it does not stop Overlord of the Balemurk's attack trigger, so keep other plans for those. Grafdigger's Cage stays in the sideboard: their lines return cards to hand or exile and return permanents, so it has almost nothing to do in this matchup. Giant's Boulder is the cut because it is slow, does little against their cheap Thoughtseize-based disruption, and can be destroyed by Witch Enchanter. Keep Karn, the Great Creator in, since its -2 can fetch sideboard artifacts like Torpor Orb or Trinisphere.