Hydroblast and Blue Elemental Blast have no legal targets since the opponent's maindeck is entirely blue with no artifacts, so they stay in the sideboard. Relic of Progenitus directly attacks the graveyard-density engine that powers Tolarian Terror and Cryptic Serpent, shrinking their cost reduction and making them clunky 6-7 mana threats again. Agony Warp and Arms of Hadar are weak here since Delver of Secrets and the serpents either dodge the power reduction (both serpents have 5+ toughness) or aren't on board yet when you need the mana up, so they're the easiest cuts. Okiba-Gang Shinobi punishes a deck that wants to hold up cheap cantrips and counterspells by stripping two cards from their hand on a connect, disrupting their plan to rebuild graveyard fuel. Keep Counterspell, Dispel, and Spellstutter Sprite in to fight through their permission suite and protect your own threats.