This matchup is a race against their colorless Eldrazi beaters and Urza's Saga value engine, so Consign to Memory is excellent at countering their colorless spells like Emrakul, the Promised End, Devourer of Destiny, and Kozilek's Command for one mana each. It can also counter triggered abilities, such as the cast triggers on Emrakul and Devourer of Destiny. Celestial Purge does nothing here, since it only exiles black or red permanents and their deck is green/colorless, so it stays out. Nihil Spellbomb comes in instead as cheap graveyard hate: it exiles their graveyard, which blunts Emrakul's cost reduction, turns off Shifting Woodland's delirium, and undercuts the value from Malevolent Rumble putting cards into their graveyard. It does not stop Urza's Saga from finding its artifact. Griselbrand is a clunky, black-heavy top end that comes out, since they have answers like Kozilek's Command and Devourer of Destiny's cast trigger, which exiles a colored permanent. One Faithful Mending is too slow against their proactive clock, so it comes out. Spell Pierce is weak because it only hits noncreature spells and only taxes two, while many of their key threats (Emrakul, Devourer of Destiny, Sowing Mycospawn) are creatures. Consign to Memory is the better tool.

Consign to Memory is premium here since it stops colorless spells and triggered abilities for one mana, letting us counter Kozilek's Command, Devourer of Destiny, or the Eldrazi Spawn token-creation trigger off Basking Broodscale that fuels their infinite combo. Celestial Purge stays in the board: their deck is green and colorless, with no black or red permanents to exile, and Glaring Fleshraker is colorless, so it is not a legal target. Nihil Spellbomb is a modest include. It exiles the cards Malevolent Rumble puts into their graveyard, which also trims Emrakul's cost reduction, but it is not our main plan. Our real answers are the counters, used on their colorless spells and on the Broodscale Spawn trigger before the loop starts. Spell Pierce is weak here because their Spawn tokens make it easy to pay for. Griselbrand and extra card draw are too slow against a deck that can go infinite, so we prioritize interaction over our own value engine.

Izzet Prowess is a fast aggressive deck full of one-mana cantrips and burn, and Consign to Memory counters colorless spells like Mishra's Bauble while also shutting off key triggered abilities for one mana at instant speed. Subtlety can flash in to tempo-tax a Dragon's Rage Channeler or Slickshot Show-Off and buy a turn while also being relevant against anything with evoke-adjacent value. Griselbrand is too slow and gets raced by their low curve, and Faithful Mending doesn't do enough to stabilize against the speed of Monastery Swiftspear starts. Spell Pierce is replaced by the strictly more flexible Consign to Memory in a deck where countering noncreature spells matters less than blanking their colorless cantrips and triggers.