msem-instigator

{T}, Pay 1 life: Add {G}.
{8}{G}, Exile Singers' Grove from your hand: Creatures you control get +7/+7 until end of turn.

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

Whenever Skeigr, Skhorvall Flagship attacks, it deals 3 damage divided as you choose among one, two, or three targets.
Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Ship Vehicle becomes an artifact creature until end of turn.)

{T}, Sacrifice Skeletal Oasis: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

At the beginning of each upkeep, choose one or more —
• Untap target artifact.
• Untap target creature.
• Untap target land.

Equipped creature gets +0/+3 and has menace. (It can't be blocked except by two or more creatures.)
Equip {3}

{T}, Discard your hand: If two or more cards were discarded this way, search your library for a card and put that card into your hand, then shuffle.

Sky-High Spires enters the battlefield tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Equipped creature gets +2/+2.
Whenever equipped creature deals combat damage to a player, you may put a permanent card with mana value 2 or less from your hand onto the battlefield.
Equip {2}

Skylight Fortress enters the battlefield tapped.
When Skylight Fortress enters the battlefield, you may search your library for a card named Skylight Fortress, reveal it, put it into your hand, then shuffle.
{T}: Add {C}.

At the beginning of combat on your turn, target creature you control with flying gets +1/+1 until end of turn.

Slaughterkeg can't attack or block.
While an opponent is choosing targets as part of casting a spell they control or activating an ability they control, that player must choose at least Slaughterkeg if able.
When Slaughterkeg dies, draw a card.

Identity — As long as you control at least two other creatures that share a creature type with Slicing Steer, Slicing Steer and creatures you control that share a creature type with it get +1/+0 and have menace.

Equipped creature has “{1}, {T}: This creature deals 1 damage to any target.”
Whenever equipped creature deals damage to a creature with power 5 or greater, sacrifice Sling of the Meek. If you do, destroy that creature.
Equip {3}

Slipsand Oasis enters the battlefield tapped unless you played it from exile.
{T}: Add {W} or {B}.

Slipstream Horizon enters the battlefield tapped.
{T}: Add {U} or {R}.
{U}{R}, {T}, Sacrifice Slipstream Horizon: Conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

(Transform this if it's not attached to a creature. Pay {2}{W} as a sorcery to unattach it.)
Enchant creature you control
Slopestrider's Chariot's rider gets +1/+1 and has double strike.

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

When Smashing Brute enters the battlefield, 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.

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.)

{T}: Add {C}.
{T}: Add one mana of any color. You can't spend this to cast spells from your hand.

When Snagged Truck enters the battlefield, investigate three times. (Create three colorless Clue artifact tokens with “{2}, Sacrifice this: Draw a card.”)
Snagged Truck can't attack or block as long as you control a Clue.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

Snow Drift enters the battlefield tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may put that card into your graveyard.)
{T}: Add {U}.
{4}{U}: Snow Drift becomes an Elemental creature. (This effect lasts indefinitely.)

At the beginning of your end step, you may put a progress counter on Snowclearer.
[PROGRESS 1-2] Sacrifice Snowclearer: Add {C}.
[PROGRESS 3+] Sacrifice Snowclearer: Add two mana of any one color.