msem-instigator

Sludge-Gill Fox can't be blocked as long as it's attacking alone.
Whenever Sludge-Gill Fox deals combat damage to a player, you may draw a card.

{2}, Remove a +1/+1 counter from a creature you control: Draw a card.

Advance {5}{B}{B} (Cast this for {5}{B}{B} to advance it as it enters. {5}{B}{B}: Advance this as a sorcery.)
Whenever Sluiceway Collector advances, put a permanent card from a graveyard onto the battlefield under your control.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
{2}{B}, Sacrifice Sluiceway Shrieker: Put the bottom card of your library into your hand.

Deathtouch
When Slum Scrounger enters, put up to two target creature cards in your graveyard on top of your library in any order.

Defender
Whenever Slumbering Bear is dealt damage, put a +1/+1 counter on it.
Remove a +1/+1 counter from Slumbering Bear: It can attack as though it didn't have defender this turn.

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Slums Thug gets +1/+1 and has menace as long as you've gained life this turn.

First strike
{2}{R}: Monstrosity 2. (If this creature isn't monstrous, put two +1/+1 counters on it and it becomes monstrous.)

When Slyten Analyst enters, you may search your library for a card, then shuffle and put that card on top. If you do, you lose 2 life.

Whenever Slyten Connoisseur attacks, crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)
Once each turn, when an artifact you control dies, you may pay 1 life. If you do, draw a card.

{T}: Add {C}.
{4}, {T}, Sacrifice Slyten Crystal Motherlode: Add {W}{U}{B}{R}{G}.

Flying
{R}: Slyten Ignitor gets +1/+0 until end of turn.

Whenever Slyten Jewel Runner attacks, target creature can't block until end of turn.
Augmented — At the beginning of your end step, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Slyten Jewel Runner.

Whenever you cast a noncreature spell, Slyten Technician gets +1/+0 until end of turn, then scry 1.

When Smashing Brute enters, target nonbasic permanent loses all abilities until your next turn.
Foresight — Whenever you draw your second card each turn, you may exile Smashing Brute. If you do, return it to the battlefield.

When Smirk enters, add the top two cards of your library to your evil plan. (Look at them, then exile them face-down. You may pay {7} once a turn as a sorcery to cast any number of cards in your evil plan without paying their mana costs.)
Whenever you cast your second spell each turn, you draw a card and you lose 2 life.

When Smokeweaver Initiate dies, draw a card.

Equipped creature gets +0/+2 and has menace.
Equip {1}

Whenever equipped creature attacks, it gets +3/+3 until end of turn.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Equipped creature gets +2/+1.
Whenever equipped creature blocks or becomes blocked by a creature, it deals 2 damage to that creature.
Equip {2}

Defender
{T}: Smoldering Djinni deals 1 damage to each opponent.
Whenever you cast a red spell, untap Smoldering Djinni.

When Smoldering Husk dies, it deals 2 damage to any target.
{2}{R}: Smoldering Husk gets +2/+0 until end of turn.

Whenever you discard an instant or sorcery card, you may cast it from your graveyard. (You still pay its costs.)
Spells you cast from anywhere other than your hand cost {1} less to cast.

{2}, Return a creature you control to its owner's hand: Smooth Musician gets +1/+1 and gains lifelink until end of turn.