“Familiars is a blue-white Pauper value deck. Sunscape Familiar makes blue spells cheaper and God-Pharaoh's Faithful gains life off them; both are low-power walls (0/3, 0/4) that hold the ground while Archaeomancer and Mulldrifter are re-used with Ephemerate, Ghostly Flicker and Snap, and Archaeomancer returns those spells to hand, grinding out card advantage over a long game. It wins slowly and plays defense, so against aggressive decks its sideboard is about blanking combat, not racing. Sideboard roles: Stonehorn Dignitary (repeated with Ephemerate rebound and Ghostly Flicker to skip combat turn after turn) is the key card against go-wide, flying and aura-based aggro; Remove Soul answers creature-heavy decks and Steel Sabotage answers artifact-based ones; Blue Elemental Blast only matters against red cards; Negate answers auras, burn and other noncreature spells; Thraben Charm's graveyard-exile mode punishes graveyard-reliant decks (delve, flashback, Tolarian Terror's cost reduction). Goliath Paladin's initiative is a liability against decks with many evasive or trampling attackers, which take the initiative straight back; it belongs only in slow, creature-light matchups. Last Breath is best on power-2-or-less creatures whose value is ongoing (Guttersnipe), not ones whose value was an enters trigger.”
Missing sideboard cards? The full 15-card sideboard runs about $14.05.
Buy sideboard on ManapoolEvery card this opponent casts is red, so all 4 Blue Elemental Blast come in as efficient one-mana answers to Lightning Bolt, Fiery Temper, Fireblast, Guttersnipe and Kessig Flamebreather. The 2 Last Breath exile Guttersnipe or Kessig Flamebreather before they rack up damage off the deck's cheap spells. Prohibit stays in since it counters most of their curve (Bolt, Fiery Temper, Lava Dart, Faithless Looting, cheap creatures), so cut the slow Meeting of Minds and all 4 Lorien Revealed, which are too passive against this clock. God-Pharaoh's Faithful and Sunscape Familiar remain key walls to buy time while Blue Elemental Blast and Last Breath pick off threats.
Dimir Control has no red cards, so Blue Elemental Blast has no targets and stays in the sideboard. Steel Sabotage does have legitimate targets in the artifact creatures Baleful Strix and Mukotai Ambusher. It can counter either one as a spell or bounce it once it's in play. But that's only five artifacts in the whole deck, and bouncing Baleful Strix just lets them replay it and draw again, so it's too narrow to bring in and stays in the sideboard. Negate is already in the maindeck answering their noncreature spells, and Thraben Charm's graveyard mode can exile their graveyard to stop Plunder the Trollshaws from being flashed back. Remove Soul would be largely redundant with Prohibit against their cheap creatures (Baleful Strix, Spellstutter Sprite). The matchup is a grind of card advantage engines on both sides, so the existing 75 is already well-suited and no changes are needed. Keep leaning on Archaeomancer and Ephemerate loops to out-value their Thorn of the Black Rose monarch plan.
Spy Combo is entirely green and black creatures and sorceries with no red or artifact permanents of note, so Blue Elemental Blast, Hydroblast, and Steel Sabotage all have no legal targets and stay in the sideboard. Remove Soul could hit their creature spells but their key engine pieces (Overgrown Battlement, Saruli Caretaker, Winding Way, Lead the Stampede) are mostly already resolving mana dorks and card draw rather than something worth a dedicated counter slot over Prohibit. The existing maindeck Prohibit and Negate already provide reasonable interaction against their ramp and card advantage. This matchup is primarily a grind where the deck's walls and recursive card advantage should outlast their go-wide plan without changes.