Mainboard (60)
Creatures (18)
Instants (18)
Sorceries (8)
Boros Energy applies fast pressure with Goblin Bombardment and Ragavan; Nature's Claim destroys their Goblin Bombardment, which would otherwise sacrifice your combo creatures in response to the stack. Mystical Dispute answers their key white or red threats for one blue mana. Into the Flood Maw bounces their key permanent at instant speed to protect your combo turn. Repudiate/Replicate and Disciple of Freyalise are slow and don't apply pressure fast enough; Nourishing Shoal is combo-adjacent and can be reduced. They board Celestial Purge targeting Griselbrand or Atraxa — have Pact of Negation ready to protect your combo pieces.
Jeskai Blink has Solitude, Consign to Memory, and Teferi that can exile or bounce your combo pieces mid-stack; Mystical Dispute counters these for one blue mana since the entire deck is blue or white. Into the Flood Maw bounces an interfering permanent on your combo turn. Abhorrent Oculus provides an alternate threat that is difficult for Solitude to profitably exile. Repudiate/Replicate and Disciple of Freyalise are slow; Hooting Mandrills is your Neoform/Evolution target and can be trimmed when you have Abhorrent Oculus. Veil of Summer in your main deck is crucial here — cast it in response to their interaction to protect the combo stack.
Affinity boards Grafdigger's Cage and Vexing Bauble to disrupt your creature-based combo; Nature's Claim destroys Grafdigger's Cage, Tormod's Crypt, or Pithing Needle (naming Neoform) for one mana. Mystical Dispute counters Kappa Cannoneer or Weapons Manufacturing. Into the Flood Maw bounces their hate pieces at instant speed. Disciple of Freyalise and Nourishing Shoal are slow setup cards against a deck that kills on turn three. Your plan is to clear their hate pieces then execute Neoform or Eldritch Evolution into Griselbrand on turn two or three.