Not on Arena (1): Thror's Map. Arena will skip it on import.
Missing sideboard cards? The full 15-card sideboard runs about $114.
Buy sideboard on ManapoolMono Green wants to flood the board with mana dorks, landfall triggers, and Sapling Nursery Treefolk tokens, so a second set of Pinnacle Starcage exiles Llanowar Elves, Sazh's Chocobo, and other artifacts and creatures with mana value 2 or less, while the extra copy maximizes the chance of catching the right wave. Be aware that it also exiles our own cheap artifacts, and it does not touch Mossborn Hydra, Icetill Explorer, or Mightform Harmonizer, which are mana value 3 or higher. Rest in Peace is a minor hedge: it exiles Esper Origins before it can be flashed back and stops Icetill Explorer from replaying lands out of the graveyard. Seam Rip has the same mana-value-2 ceiling as Starcage, so it also misses Mossborn Hydra, Icetill Explorer, and Mightform Harmonizer. With four Starcage in the 75 the effects overlap, so trim one Seam Rip along with underperforming utility artifacts.
Dimir Midrange's game plan runs through Enduring Curiosity, Kaito, and a pile of noncreature value spells like Requiting Hex and Strategic Betrayal, so Negate is live against most of their key engine pieces and removal. Spell Pierce taxes their Kaito or removal when you're ahead on tempo. Rest in Peace exiles all graveyards, shutting off Enduring Curiosity's return-from-graveyard trigger permanently and hurting any flashback/delve elements they bring in. Seam Rip is too narrow here since Kaito and Enduring Curiosity are both above mana value 2, so cut it for the more impactful interaction.
BRG has several ETB triggers on creatures, notably Biotech Specialist (Lander token), The Sackville-Bagginses (sacrifice for a card and Treasure), Wolverine (fight) and Rottenmouth Viper (enter trigger), so Torpor Orb switches those off. It does not stop dies triggers like Greedy Freebooter and Callous Inspector, or noncreature permanents like Obsessive Pursuit. The Ooze is a noncreature artifact, not a blocker or attacker. Its value is exiling creature cards from their graveyard to blank Lively Dirge's reanimation mode, while making Mutagen tokens along the way. Voice of Victory's mobilize tokens help race their go-wide sacrifice shell and stop them from disrupting your turn with instant-speed spells. Seam Rip still answers cheap permanents like Gene Pollinator and Greedy Freebooter, but we trim it along with Braided Net and Thror's Map to make room for the stickier anti-synergy pieces.