Silvergill Douser

Creature — Merfolk Wizard (1/1)

: Target creature gets -X/-0 until end of turn, where X is the number of Merfolk and/or Faeries you control.

Skyclave Aerialist // Skyclave Invader

Creature — Merfolk Scout // Creature — Phyrexian Merfolk Sco (2/1)

Flying
: Transform Skyclave Aerialist. Activate only as a sorcery. ( can be paid with either or 2 life.)

Skyclave Invader

Flying
When this creature transforms into Skyclave Invader, look at the top card of your library. If it's a land card, you may put it onto the battlefield. If you don't put the card onto the battlefield, put it into your hand.

Skyshroud Condor

Creature — Bird (2/2)

Cast this spell only if you've cast another spell this turn.
Flying

Snapcaster Mage

Creature — Human Wizard (2/1)

Flash
When Snapcaster Mage enters the battlefield, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Soldevi Machinist

Creature — Human Wizard Artificer (1/1)

: Add . Spend this mana only to activate abilities of artifacts.

Spectral Adversary

Creature — Spirit (2/1)

Flash
Flying
When Spectral Adversary enters the battlefield, you may pay any number of times. When you pay this cost one or more times, put that many +1/+1 counters on Spectral Adversary, then up to that many other target artifacts, creatures, and/or enchantments phase out.

Spellstutter Sprite

Creature — Faerie Wizard (1/1)

Flash
Flying
When Spellstutter Sprite enters the battlefield, counter target spell with mana value X or less, where X is the number of Faeries you control.

Stern Proctor

Creature — Human Wizard (1/2)

When Stern Proctor enters the battlefield, return target artifact or enchantment to its owner's hand.

Stitcher's Apprentice

Creature — Homunculus (1/2)

, : Create a 2/2 blue Homunculus creature token, then sacrifice a creature.

Stonybrook Angler

Creature — Merfolk Wizard (1/2)

, : You may tap or untap target creature.

Storm Fleet Aerialist

Creature — Human Pirate (1/2)

Flying
Raid — Storm Fleet Aerialist enters the battlefield with a +1/+1 counter on it if you attacked this turn.

Stormscape Familiar

Creature — Bird (1/1)

Flying
White spells and black spells you cast cost less to cast.

Stratus Dancer

Creature — Djinn Monk (2/1)

Flying
Megamorph (You may cast this card face down as a 2/2 creature for . Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When Stratus Dancer is turned face up, counter target instant or sorcery spell.

Straw Soldiers

Creature — Scarecrow Soldier (1/3)

Supreme Phantom

Creature — Spirit (1/3)

Flying
Other Spirits you control get +1/+1.

Svyelunite Priest

Creature — Merfolk Cleric (1/1)

, : Target creature gains shroud until end of turn. Activate only during your upkeep. (It can't be the target of spells or abilities.)

Sworn Guardian

Creature — Merfolk Warrior (1/3)

Tah-Crop Skirmisher

Creature — Naga Warrior (2/1)

Embalm (, Exile this card from your graveyard: Create a token that's a copy of it, except it's a white Zombie Naga Warrior with no mana cost. Embalm only as a sorcery.)

Talas Explorer

Creature — Human Pirate Scout (1/1)

Flying
When Talas Explorer enters the battlefield, look at target opponent's hand.

Talas Merchant

Creature — Human Pirate (1/3)