Izzet Spellementals grows Hearth Elemental and Eddymurk Crab through a dense cantrip chain, so Crystal Barricade is a great wall that shuts down their small early creatures while its hexproof clause protects us from Prismari Charm and Burst Lightning. Spell Pierce disrupts their low curve of Opt, Sleight of Hand, and Prismari Charm, denying the spell-triggered growth those cards feed. We cut Seam Rip because most of their key permanents (Hearth Elemental, Eddymurk Crab, Sunderflock) cost more than 2, and drop the narrow Mockingbird/Shardmage's Rescue and a land to keep our curve low and interactive.

Mono-Green Landfall ramps with Llanowar Elves into Mightform Harmonizer and Ba Sing Se-fueled Earthbend triggers, so we need clean removal for their bigger threats: Erode answers a doubled Mightform Harmonizer or Icetill Explorer before it runs away with the game, and Seam Rip can exile an early Llanowar Elves to blunt their acceleration. We shave Sewer-veillance Cam since tempo-tapping matters less against a ramp deck that just keeps landing bigger bodies, and cut the narrow Mockingbird/Shardmage's Rescue for more proactive removal.

Jeskai Control wants to resolve Jeskai Revelation and grind with Stock Up/Accumulate Wisdom, so we bring in a full package of countermagic: Spell Pierce taxes their cheap card selection and can flat-out stop a kicked spell if they are tapped out, while Disdainful Stroke is a hard counter for Jeskai Revelation and Thor, God of Thunder. Sage of the Skies gives us a resilient lifelink flier that survives their sweepers like Pyroclasm and races Great Hall of the Biblioplex in a long game. We trim some copies of Nurturing Pixie and all copies of Seam Rip since their early board is mostly noncreature permanents and cheap Lessons that dodge Seam Rip's MV2-or-less clause, and Mockingbird/Shardmage's Rescue are too narrow when they have little board worth copying or protecting.