msem-instigator

Enchant creature
Enchanted creature gets +2/+3.
As long as enchanted creature has a +1/+1 counter on it, it has vigilance.

Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Create a 3/3 black Demon Horror creature token.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

Whenever Stealer of Secrets deals combat damage to a player, draw a card.

Equipped creature gets +1/+0 for each artifact you control.
Equip—Sacrifice an artifact.

Flying
Whenever a player shuffles their library, Steamquiver Strix deals 2 damage to that player.

Flying
Embellish {4}{U} (If you cast this spell for {4}{U}, create a 1/1 blue Thopter artifact creature token with flying when it enters.)

Whenever Steelcrusher Viking blocks or becomes blocked by a creature, destroy up to one target Aura or Equipment attached to that creature.

Target creature gets +1/+5 until end of turn.
Draw a card.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever Steelhoof Battlechief attacks, another target attacking creature you control gets +2/+2 and gains trample until end of turn.

Whenever Steward of Silence blocks, you get a glory counter. (You lose glory counters before life. A player with ten or more glory counters wins the game.)

Target opponent discards a card at random. If that card's mana value is 3 or less, you may cast it without paying its mana cost.

Still-Smoke Hunter gets +2/+1 and is a Beast in addition to its other types while it's tapped.
Revive {3}{B} ({3}{B}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)

Creature cards in your graveyard have revive. The revive cost is equal to their mana cost. (Pay that creature's mana cost, Exile that card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

When Stillmarsh Brinecatcher enters, return another target nonland permanent to its owner's hand.
At the beginning of your end step, if you control a permanent with mana value 5 or greater, you may sacrifice Stillmarsh Brinecatcher. If you do, draw a card and create a 3/2 colorless Horror creature token.

If you would draw a card, you may skip that draw. If you do, create a tapped Treasure token and exile the top card of your library. You may play that card this turn.

Enchant creature
Enchanted creature's activated abilities can't be activated.
Prevent all damage that would be dealt by enchanted creature.

Menace
Whenever you discard a card, Stillsong Enforcer deals 1 damage to target opponent or planeswalker.

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
At the beginning of your end step, each cursed opponent loses 1 life. You gain life equal to the life lost this way.

When Stilthorpe Falconer enters, create a 1/1 white Bird creature token with flying.

Flying
Whenever you cast your first spell each turn, add {U}{U}, {U}{R}, or {R}{R}.
Whenever you cast your second spell each turn, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Whenever you cast your third spell each turn, Stirring Igmel deals 3 damage to each opponent.

When Stolen Light enters, exile target nonland permanent an opponent controls until Stolen Light leaves the battlefield.
{W}{U}{B}{R}{G}: Put a permanent card exiled with Stolen Light onto the battlefield under your control. It's a 3/3 Horror creature in addition to its other types.

Destroy target artifact or nonbasic land.

Whenever you cast a spell, if it isn't your main phase, you may have Stoneshrine Guardian's base power and toughness become 4/1 or 1/4 until end of turn.

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +2/+2.