msem-instigator

Vigilance
Seawise Swain gets +1/+1 as long as you control an artifact.
Seawise Swain gets +1/+1 as long as you control an enchantment.

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a creature card that shares a creature type with the sacrificed creature with mana value less than or equal to X plus the sacrificed creature's mana value, put it onto the battlefield, then shuffle.

When Sending Stones enters, harmonize twice. (To harmonize, trigger up to one harmony of a permanent you control.)
If you would harmonize, you may trigger a harmony of a permanent card in your graveyard instead.

[+1]: Remove all counters from target permanent.
[+1]: Each opponent discards a card.
[–2]: Exile target creature or planeswalker card from your graveyard with mana value less than or equal to the number of lands you control. If you do, create a token that's a copy of it.
[–7]: Each opponent gets an emblem with “At the beginning of your upkeep, you lose 7 life unless you sacrifice seven permanents.”

As long as it's your turn, Seto San is a 3/3 Human Warrior creature with indestructible.
[+1]: Up to one target creature you control gains lifelink until end of turn.
[0]: Create a 1/1 white Warrior creature token.
[–X]: Search your library for an Aura or Equipment card with mana value X and put it onto the battlefield, then shuffle.

When Shadowbinder Touka enters or attacks, exile up to one target creature card from a graveyard.
You may play creature cards exiled with Touka.
Sacrifice another creature: Add two mana in any combination of colors. You can't spend this mana to cast spells from your hand. If this mana is spent to cast a creature spell, that creature enters with a finality counter on it.

When Shala Na enters, each player chooses a creature they control, then sacrifices the rest.
[+1]: Up to one target creature you control gains double strike and haste until end of turn.
[–6]: You get an emblem with “Whenever a creature dies, each opponent loses 2 life.”

Pressure {2}{G}{G} (You may cast this spell for its pressure cost if there are seven or more cards in your graveyard.)
Trample, hexproof
Shambling Dreadreef's power and toughness are each equal to the total number of land cards you own on the battlefield and in your graveyard.

You may play Shanty Town from your graveyard as long as seven or more cards are in your graveyard.
Shanty Town enters tapped.
{T}: Add {W} or {B}.
Cycling {1}{W}{B} ({1}{W}{B}, Discard this card: Draw a card.)

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

As an additional cost to cast this spell, discard a card.
Choose two. You may choose the same mode more than once.
• Draw a card.
• Return target card with a cycling ability from your graveyard to your hand.

This spell has flash as long as an opponent is cursed.
Return target creature to its owner's hand.
Draw a card.

Flying
When Shoal Raker enters, draw a card if an opponent is cursed.

Spells your opponents cast that target Shoalshine cost an additional {2} to cast.
Concord — {T}: Draw a card. Activate only if there are four or more card types among permanents you control.

Flying
Sacrifice a creature: Shrieking Nightwing gets +1/+1 until end of turn.

Flying
Resolute — At the beginning of combat on your turn, Shrill Griffin gains vigilance until end of turn if its power is greater than its base power.

Enchant creature
When Shrouded Spoils enters, draw two cards.
Enchanted creature can't be blocked.

{T}: Scry 1.

Silent Doom enters tapped.
You may cast Silent Doom from your graveyard as long as you sacrificed a permanent this turn.
Cycling {B} ({B}, Discard this card: Draw a card.)

Silent Hunt deals 3 damage to target creature and you gain 3 life.
Forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

Whenever Silt Lurker deals combat damage to a player, mill three cards, then draw a card if seven or more cards are in your graveyard.
Cycling {G} ({G}, Discard this card: Draw a card.)

When Silt Miner enters, you may salvage an artifact or creature card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Counter target spell.
Forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

Draw a card, then forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

Resolute — Skerry Serpent must be blocked if able as long as its power is greater than its base power.