msem-instigator

Flash
When Stalker in the Mist enters, up to one target creature gets -1/-0 until end of turn.

Stalwart Guardian has first strike as long as it's attacking.
Augmented — When Stalwart Guardian enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, create two 1/1 blue Elemental creature tokens with flying.

Other creatures you control named Starfall Dancer get +2/+2.

Whenever Starfall Instructor attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Each opponent loses 2 life.

Whenever Stargaze Spirit or another creature dies, you may gain 1 life.
Revive {3}{W} ({3}{W}, 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.)

At the beginning of your end step, you may sacrifice a permanent. When you do, return target creature card from your graveyard to your hand.

Flying
Whenever an opponent draws a card except for the first time each turn, create a 1/1 blue Elemental creature token with flying.
Foresight — Whenever you draw your second card each turn, creatures you control get +1/+1 until end of turn.

Menace
Discard a creature card or sacrifice a creature or exile a creature card from your graveyard: Put a +1/+1 counter on Starving Stalker. Activate only once each turn.

{1}{W}: Untap Steadfast Infantry.

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

When Steamwork Musicians enters, creatures you control get +1/+0 until end of turn.

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)

Steelborn Apprentice gets +1/+1 as long as you control an Equipment.

Vigilance
Renown 2 (When this creature deals combat damage to a player, if it isn't renowned, put two +1/+1 counters on it and it becomes renowned.)
{T}: Prevent the next X damage that would be dealt to target creature this turn, where X is Steelclad Investigator's power.

Flash
Advance {3}{W} (Cast this for {3}{W} to advance it as it enters. {3}{W}: Advance this as a sorcery.)
Whenever Steelwoven Soldier advances, it gets +2/+2 until end of turn.

Trial 3 (As you cast this spell, an opponent of your choice may pay 3 life. If they don't, they fail the trial.)
When Steeple Deadeye enters, if the trial was failed, you gain 3 life and put a +1/+1 counter on Steeple Deadeye.

When Stiff Butler enters, search target player's library for up to two cards and exile them. Then that player shuffles.

When Still-Smoke Skirmisher dies, each opponent loses 1 life and you gain 1 life. Then return Still-Smoke Skirmisher to the battlefield at the beginning of the next end step if it was sacrificed.

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.

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

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

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Whenever you cast a spell that doesn't share a color with Stinging Hunter, each opponent loses 1 life.

Stinging Swordfish has first strike as long as it's attacking.
When Stinging Swordfish dies, create an Equipment enchantment artifact token named Fish Sword with “Equipped creature gets +3/+1,” “Equipped creature has first strike as long as it's attacking,” and equip {2}. You may attach that token to a creature you control.

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.