Missing sideboard cards? The full 15-card sideboard runs about $32.21.
Buy sideboard on ManapoolMono-Green Landfall wants to grow Mossborn Hydra and Mightform Harmonizer off repeated land drops from Fabled Passage and Earthbender Ascension. Get Lost is unconditional removal that answers an oversized Hydra or Icetill Explorer before it snowballs. Bovine Intervention trades for another big threat, granting only a vanilla 2/2 Ox in return. We shave Formidable Speaker and the singleton Imodane's Recruiter since neither interacts with their growing threats.
Dimir Midrange is loaded with cheap disruption and countermagic (Spell Pierce, We Say Thee Nay!, Spell Snare) plus two-mana threats like Floodpits Drowner. Seam Rip cleanly exiles low-cost permanents like Floodpits Drowner or Spyglass Siren. Surrak, Elusive Hunter can't be countered and punishes their removal-heavy Requiting Hex and Bitter Triumph plan by drawing cards when targeted. Interdimensional Web Watch is too slow and vulnerable to their counters, so it comes out along with some Formidable Speakers and the singleton Imodane's Recruiter.
BRG shares the same sacrifice-value shell as the Jund Sacrifice list (Callous Inspector, Gene Pollinator, The Sackville-Bagginses, Obsessive Pursuit), so the plan mirrors that matchup. Leatherhead, Swamp Stalker's hexproof counter dodges their removal package while trample punches through their small blockers. Bovine Intervention picks off a key threat like Vinereap Mentor or Umbral Collar Zealot. We again cut the slower Interdimensional Web Watch and one Aang, at the Crossroads for a leaner, more resilient game plan.