Mono Green Landfall wants to flood the board with mana dorks and ramp into Mossborn Hydra and Mightform Harmonizer, so Clarion Conqueror is huge here. Its static ability stops activated abilities of creatures, which shuts off Llanowar Elves' mana ability and Keen-Eyed Curator's graveyard-exile ability, and it is a 3/3 flier that blocks well. It does not stop Earthbender Ascension or Ba Sing Se, so don't count on it for those. It also turns off our own Springleaf Drums, so two Drums come out. Seam Rip is better than it first looks: it cleanly exiles Llanowar Elves and Sazh's Chocobo, so both copies stay in. Spider-Sense comes in to counter their sorceries such as Esper Origins and Shared Roots, or a landfall trigger like Mossborn Hydra's doubling or Mightform Harmonizer's power doubling. Practiced Offense is too slow against their ramp plan and comes out for more impactful threats and interaction. Keep Get Lost and Erode in as answers to Mossborn Hydra, but remember Erode gives them a basic land, which triggers landfall.

Rest in Peace is excellent against Dimir Midrange, shutting off Enduring Curiosity's recursion, Kaito's ninjutsu loop potential, and any graveyard value from Spyglass Siren Maps or flashback effects, while also hurting their own deck minimally since they aren't heavily graveyard-dependent beyond Kaito and Curiosity. Spider-Sense lets us counter their key instants like Bitter Triumph or Requiting Hex at a discount. Seam Rip is weaker here since Kaito and Spyglass Siren are their only 2-or-less targets and they have plenty of ways to protect or outvalue it. Abandoned Air Temple is swapped since the matchup is a grindy midrange fight where we want more actual mana sources; trimming to our other basics and duals keeps the manabase functional with the land cut matched elsewhere is avoided, so instead Nurturing Pixie, a weak 1/1 that doesn't impact their removal-heavy plan, comes out alongside two copies of Seam Rip.

BRG is a grindy value midrange deck full of 2-4 toughness creatures, so Clarion Conqueror is a great flying blocker that also turns off Gene Pollinator's mana ability and The Sackville-Bagginses's sacrifice triggers indirectly by not stopping them but still trading well in combat. Spectacular Spider-Man flashes in as a surprise blocker or attacker and can sacrifice itself to protect your board from their removal-heavy sideboard plan (Maelstrom Pulse, Witherbloom Charm). Seam Rip is narrow since most of their early creatures like Gene Pollinator and Greedy Freebooter are not the format's biggest issues and the grindy games favor proactive threats, so it comes out alongside the slower Practiced Offense.