msem-instigator

Haste
Whenever Shala's Phantasm attacks, you may sacrifice a creature. If you do, Shala's Phantasm deals 3 damage to any target.

When Shaman of Burning Ashes enters, return target instant or sorcery card from your graveyard to your hand. When you do, each opponent loses X life, where X is that card's mana value.

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

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.)

Look at the top three cards of your library. Put one of them into your hand, one on top of your library, and one on the bottom of your library.
Reprise {1}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Create a colorless Equipment artifact token with “Equipped creature gets +1/+1” and equip {1}. You may attach it to a creature you control.
Inscribe {3}{R} ({3}{R}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

When you cast an instant or sorcery spell, you may sacrifice Shard Flower. If you do, copy that spell. You may choose new targets for the copy.

Equipped creature gets +1/+1 and has distorted. (It can be blocked by tapped creatures but not untapped creatures.)
Equip {1}

When Shardsong Seedling enters, conjure two cards named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Discard a land card: Draw a card. Shardstorm Elemental gets +1/+0 and gains flying until end of turn. Activate only once each turn.

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

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Spell you cast cost {1} less to cast as long as it's not your turn.

Flash
Unveil {3}{B}{G} ({3}{B}{G}: Transform this. Unveil only as a sorcery.)

Creatures you control get +1/+0.
Ferocious — At the beginning of combat on your turn, creatures you control with power 4 or greater gain trample until end of turn.

Lifelink
Each other artifact creature you control enters with an additional +1/+1 counter on it.

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.

Trample
Improve {1}{R} ({1}{R}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Embattled creatures you control get +2/+0. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Equipped creature gets +1/+1.
Whenever equipped creature becomes the target of a spell or ability an opponent controls, you may return Shawl of Warding to its owner's hand. If you do, counter that spell or ability.
Equip {2}

When Shawlbinder enters, if you control a Desert, exile another target permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Target creature you control deals damage equal to its power to target creature you don't control.
Whenever a creature you control with deathtouch deals damage to an opponent, you may sacrifice that creature. If you do, return Shedding of the Coils from your graveyard to your hand.

Vigilance
Whenever one or more creatures you control deals combat damage to a player, you may discard a card. If you do, create a Function token with “Draw two cards.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

When Sheltered Diviner enters, each player mills three cards.

{T}: Add {C}.
As long as Shengin Heartland is in your graveyard, lands you control have “{T}: Add {G} or {U}.”

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.)

Shepherd of the People can't be blocked by creatures with power 2 or less.
Whenever another Citizen or Peasant you control enters, Shepherd of the People gets +1/+1 until end of turn.