Mono-Green Eldrazi leans on cheap colorless permanents like Eldrazi Spawn tokens and one- and two-mana artifacts, so Stern Scolding and Spell Snare are often dead against their actual threats (Emrakul and big creatures dodge both). Engineered Explosives can be set to blow up their mana dorks, Spawn tokens, or cheap artifact hate pieces, giving you a flexible sweeper for their low curve. Tormod's Crypt does little against their plan directly but can strip Ancient Stirrings/Malevolent Rumble value from the graveyard if they mill permanents; mostly it's a cheap, free include. Keep the core combo and countermagic suite intact since you still need to race before they assemble Eldrazi Temple into Emrakul.

This is a combo mirror where the Basking Broodscale/Blade of the Bloodchief loop cares about artifact removal and sacrifice synergies, not creature size, so Stern Scolding and Spell Snare mostly whiff on their payoff pieces. Engineered Explosives set to one mana can destroy Blade of the Bloodchief or their one-mana artifact answers (Vexing Bauble, Haywire Mite, Soul-Guide Lantern), directly disrupting the combo before it goes off. Tormod's Crypt is a low-opportunity-cost include that can strip value if they're milling permanents via Malevolent Rumble, though it won't stop the live combo once assembled. Keep your own combo suite (Goblin Charbelcher, Lotus Bloom, Whir of Invention) maximally intact since this matchup is primarily a speed race.

Izzet Prowess is a pure aggro-tempo deck with very few colorless spells, so Consign to Memory is a modest bring-in here. It can counter Mishra's Bauble, and it can counter triggered abilities such as prowess triggers, Slickshot Show-Off's pump, Dragon's Rage Channeler's surveil, and Cori-Steel Cutter's flurry trigger. Replicate lets you hit several triggers in one turn. Cori-Steel Cutter is red, so Consign cannot counter the Equipment spell itself, only its trigger. Spell Snare is excellent because their mana value 2 spells (Slickshot Show-Off, Cori-Steel Cutter, and Expressive Iteration) are all legal targets. Their one-drops like Dragon's Rage Channeler, Monastery Swiftspear, Lightning Bolt, and Preordain are mana value 1, so Spell Snare cannot touch them. Stern Scolding stays in, because Dragon's Rage Channeler (1/1), Monastery Swiftspear (1/2), and Slickshot Show-Off (1/2) all have power or toughness 2 or less as spells, so it answers every creature they cast. Preordain is cut because it is too slow in a race, and Into the Flood Maw is low-impact against a deck with few relevant permanents to bounce profitably. Prioritize resolving your combo quickly since this matchup is a pure race.