This matchup is a race between our combo and their Urza's Saga/Eldrazi mana ramp into Emrakul or Devourer of Destiny. The extra Nature's Claim lets us blow up Urza's Saga tokens or any artifact mana rock cheaply, slowing their ramp plan, while Dismember and Into the Flood Maw give us ways to remove or bounce a blocker (or a resolved Emrakul) so our combo creatures can get through. Veil of Summer is weak here since their deck is mono-green/colorless and rarely casts blue or black spells, and Wistfulness and Endurance are low-impact graveyard/artifact tools against a deck that isn't really graveyard-dependent. Keep the core combo plan the same; just prioritize resolving Allosaurus Rider or Neoform targets before they hit their top end.

Their colorless-leaning combo relies on Blade of the Bloodchief and artifact pieces like Vexing Bauble, Haywire Mite, and Soul-Guide Lantern, so the extra Nature's Claim copies are excellent at stripping Blade of the Bloodchief off Basking Broodscale before the loop starts. Dismember gives us a cheap way to kill Basking Broodscale or Glaring Fleshraker in response to the combo attempt, since -5/-5 handily kills either. Veil of Summer and Wistfulness are weak since this opponent is mono-green/colorless and rarely casts blue or black spells to punish, and we'd rather have proactive artifact/creature answers than protection spells here. Race them if possible, but hold up Nature's Claim and Dismember as insurance against the loop going off.

Izzet Prowess is a fast aggressive deck with no artifacts or enchantments to target, so Nature's Claim and Veil of Summer (which only helps against blue/black spells being cast at us, not burn spells targeting our life/creatures) are much weaker than extra countermagic. Mystical Dispute is excellent since many of their spells (Preordain, Expressive Iteration, Lightning Bolt is not blue but their deck runs blue cards like Preordain and Expressive Iteration) are blue, making it cheap and efficient at protecting our combo turn. A second Pact of Negation gives us more free protection to push through our combo before they can race us with burn to the face or to our creatures. We want to resolve our combo as fast as possible since their clock is fast and unforgiving.