Mono Green is almost entirely green spells (and colorless), so Flashfreeze is a clean counter for their key threats like Mossborn Hydra, Icetill Explorer, and Mightform Harmonizer. Qarsi Revenant's flying deathtouch lifelink body is excellent at blocking their ground creatures and racing, while Negate picks off Earthbender Ascension or Sapling Nursery. Duress is weak here since green decks run few relevant noncreature spells in hand, and Theorix Charm's counter mode is less useful against a deck that isn't casting many countermagic-vulnerable spells late; Spell Snare has few 2-mana targets in their list. Keep Requiting Hex and Bitter Triumph in to handle their creature-heavy plan.

This is the mirror-adjacent matchup against another Dimir deck, so Strategic Betrayal is strong: it forces them to exile a creature of their choice plus their entire graveyard, denying Kaito ninjutsu returns and any delve/graveyard value while also hitting their best threat. Extra Duress preempts their Requiting Hex, Bitter Triumph, and countermagic before they can use it. We trim Theorix Charm since its counter modes compete with our own Requiting Hex/Bitter Triumph for removal slots and we'd rather have unconditional discard/exile effects, and Overlord of the Balemurk is clunky against their own hand disruption and removal-heavy deck. Keep Duress mainboard copies plus these extras to strip their countermagic and discard spells first.

BRG is a creature-heavy midrange deck with removal of its own (Requiting Hex, Stir Up Trouble), so extra Duress copies strip their removal before they can use it on our threats. Doomsday Excruciator is a huge flying body that dodges their small creatures in combat and refills our hand every upkeep, which is valuable in a grindy matchup. Winternight Stories is cut since it doesn't advance our board against their creature pressure quickly enough, and The Theorist, Jace Beleren's +1 token is too slow against their aggressive creature curve and risks being attacked down by their creatures, such as Smaug the Magnificent or a Rottenmouth Viper. Keep Requiting Hex and Bitter Triumph as our primary removal against their one- and two-drops.