msem-instigator

Target creature phases out. Its controller sacrifices a creature. (Treat the phased out creature and anything attached to it as though they don't exist until its controller's next turn.)

When Shadow of Izumito dies, choose one —
• Destroy target creature that was dealt damage this turn.
• You may put a progress counter on a Project you control.

Shadowband Consul enters tapped.
{B}, Pay 2 life: Return Shadowband Consul from your graveyard to the battlefield. Activate only if an opponent lost life this turn.

Shadowcleft Hideout enters tapped.
{T}: Add {B}.
{T}, Pay 2 life, Sacrifice Shadowcleft Hideout: Draw a card.

Deathtouch
When Shadowed Apostle dies, draw a card.

({T}: Add {B}.)
Shadowed Slums enters tapped.
{B}, {T}, Reveal a black card from your hand: Target player loses 1 life.

Sacrifice Shadowfeeder: Target player loses 1 life and you gain 1 life.

When Shadowlurk enters, if a creature died this turn, put a +1/+1 counter on it.

Draw two cards. You lose 2 life. Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
When Shaman of the First Pact enters, exile up to four target creature cards from graveyards. You may cast them for as long as they remain exiled and you may spend mana as though it were mana of any type to cast them.

When Shambling Gutless enters, target player discards a card.

As long as Shambling Morass is on the battlefield or in your graveyard, it's a land in addition to its other types.
When Shambling Morass dies, you may pay {1}. If you do, you draw a card and you lose 1 life.

When Shambling Retinue dies, create a 2/2 black Zombie creature token.

Menace, lifelink
Whenever a creature enters under an opponent's control, you may have that player lose 1 life.

When Shark Slayer enters, you may destroy target creature with mana value less than or equal to the number of artifacts you control.

Flying
Glorious end — When Shattered Valkyrie dies, if it was tapped, draw a card for each creature that died this turn.
Sacrifice another creature: Shattered Valkyrie gains indestructible until end of turn.

Advance {4}{B} (Cast this for {4}{B} to advance it as it enters. {4}{B}: Advance this as a sorcery.)
Whenever Shearing Vampire advances, target player discards a card.

Revive—{B}, Discard a card. ({B}, Discard a card, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Target player discards a card.
Monument {1}{B} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Whenever Shifty Fink attacks, if you have more cards in hand than defending player, it gets +2/+1 until end of turn.

Whenever a creature you control dies, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Whenever you sacrifice a noncreature permanent, each opponent loses 1 life and you gain 1 life.

Menace
Art of war — At the beginning of your end step, if Shikai Hunters dealt damage to an opponent this turn, put a +1/+1 counter on it.

Shikai Revenant enters tapped.
At the beginning of your end step, if an opponent lost life this turn, you may return Shikai Revenant from your graveyard to your hand.

Return target creature card from your graveyard to the battlefield. Put a +1/+1 counter on it for each of its colors.

Partner with Kasoha, Keeper of Truths (When this creature enters, target player may put Kasoha into their hand from their library, then shuffle.)
Whenever Shizura, Keeper of Traditions or another legendary creature dies, target player draws two cards and loses 2 life.