Pyroblast stays in the sideboard: the only blue card in their deck is Sneaky Snacker, which keeps returning from the graveyard, so Pyroblast has almost nothing worth hitting. Electrickery is the better pick, since its overload mode ({1}{R}) deals 1 damage to each creature they control and cleanly kills Voldaren Epicure (1/1) and Sneaky Snacker (2/1). It will not kill Kessig Flamebreather (1/3) or Guttersnipe (2/2), so don't count on it against those. Prismatic Strands can blank a whole turn of their red burn and attackers, and Celestial Flare makes them sacrifice an attacking or blocking creature. Relic of Progenitus does nothing against madness since Fiery Temper is discarded into exile, not the graveyard, so it comes out. Suplex is too slow and narrow against a deck trying to race; prioritize cheap interaction and efficient early plays like Thraben Inspector and Glint Hawk instead. Keep Thraben Charm and Lightning Bolt in as premium removal for their small creatures, and keep Lembas in for the life gain.

Dimir Control has very little that our other sideboard cards interact with meaningfully — no artifacts/enchantments worth Dust to Dust, no white/black removal targets for Destroy Evil, and their key threats (Spellstutter Sprite, Faerie Seer, ninjas) aren't hit hard enough by Electrickery or Pyroblast to be worth the swap since they run almost no blue permanents worth destroying beyond small bodies already in our Galvanic Blast/Lightning Bolt range. Gorilla Shaman is minor upside against their artifact lands (Dimir Aqueduct doesn't count, but any incidental artifacts) and gives another cheap body; otherwise this matchup is close to a mainboard mirror where our proactive aggro plan and Relic of Progenitus (hits Lorien Revealed's graveyard synergies and denies Gurmag Angler delve fuel) already do work. Keep the plan minimal and proactive.

Affinity is almost entirely artifacts, making Dust to Dust extremely efficient at exiling two threats (Refurbished Familiar, Utrom Monitor, Cryogen Relic) at once, a huge tempo and card-advantage swing. Gorilla Shaman adds a cheap repeatable artifact-destruction option that can pick off a Giant's Boulder or similar mana artifact. Its ability costs {X}{X}{1}, where X is the target's mana value, so it is cheap against low-cost artifacts and gets expensive against pricier ones. That is fine value in a grindy artifact mirror-ish matchup. Relic of Progenitus does little here since this deck isn't graveyard-dependent, so it comes out; Suplex's artifact-exile mode is redundant with the Dust to Dust upgrade. Keep Dispatch and Galvanic Blast in, since Dispatch's metalcraft exile is great against their own artifact creatures and Galvanic Blast hits for 4 easily with our artifact count.