Mono Green Eldrazi ramps into big threats like Emrakul, the Promised End and Sire of Seven Deaths while using Kozilek's Command and Unholy Heat as removal; Prismatic Ending can exile ramp pieces like Utopia Sprawl (one color) and Talisman of Impulse (two colors) before they accelerate them out of our combo window. Their Kozilek's Return only deals 2 damage to each creature, so an unflipped Ral, Monsoon Mage (a 1/3) survives it. The danger is when it sits in their graveyard and they cast an Eldrazi creature spell with mana value 7 or greater, since it can then be exiled for 5 damage to each creature, so speed is important. Cut Wish and one Strike It Rich for more proactive removal since this is fundamentally a race we should usually win if uninterrupted.

This is a grindy value matchup where they flood the board with Eldrazi Spawn tokens and creature threats like Basking Broodscale and Devourer of Destiny. Prismatic Ending can exile their cheap nonland permanents, such as Basking Broodscale, Blade of the Bloodchief or Vexing Bauble, but the target's mana value must be no greater than the number of colors of mana spent, so it only reaches low-cost cards and it can't hit lands like Urza's Saga. Wear/Tear's artifact half answers Vexing Bauble or Blade of the Bloodchief, and the Tear half can destroy Urza's Saga since it is an enchantment land. Cut the slower Glimpse the Impossible and Wish since we need to be proactive and race rather than durdle, as they can grind long games with Kozilek's Command and Ancient Stirrings. Keep the rest of the combo suite, since their interaction is limited, though Kozilek's Command can exile Past in Flames from the graveyard and Devourer of Destiny's cast trigger can exile a colored permanent like Ral.

Izzet Prowess races with cheap burn and prowess creatures, so Flusterstorm is excellent both to protect our combo turn from their Lightning Bolt/Lava Dart removal and to counter their own instants and sorceries, such as Lightning Bolt, Lava Dart, and Preordain, during a critical turn. This is a pure race where our life total is the main resource against their burn plan, so cut a few cards that don't advance our clock. Keep Manamorphose, Ral, Monsoon Mage, and the ritual package intact since we need to go over the top with Grapeshot/Past in Flames before they burn us out. Untimely Malfunction stays in the sideboard since we are focused on racing rather than answering their artifacts.