msem-instigator

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you casting a noncreature spell causes an ability of a creature you control to trigger, that creature gains your choice of first strike, haste, menace, or trample until end of turn.

Create a 1/1 colorless Human creature token. Put your choice of a flying, vigilance, prowess, or hexproof counter on it. If you control a permanent with mana value 5 or greater, instead put any number of those counters and a +1/+1 counter on it.

Spells your opponents cast that target Sheltered Snowman cost {2} more to cast.
Whenever you cast a spell from exile, put a +1/+1 counter on Sheltered Snowman. It can't be blocked this turn.

Assault {2}{R}{G} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Shemesh assaults, other creatures you control get +2/+2 and gain trample until end of turn.

Choose two —
• Target creature gets +2/+0 until end of turn.
• Two target creatures can't block this turn.
• Target player discards two cards, then draws a card for each card they discarded this way.
• Shi Hou's Command deals 4 damage to target legendary creature or planeswalker.

Whenever Shianne's Guardian or another creature you control enters, you may pay {1}{R}{G}. When you do, that creature deals damage equal to its power to any target.

Archive 7 (As this enters, shuffle the top seven cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
As long as you control five or more creatures, you may play permanent cards from the archived library.

[+1]: Create two 1/1 red Satyr creature tokens.
[–1]: Until your next turn, target creature has base power and toughness X/X, where X is the number of permanents you control.
[–8]: Reveal the top card of your library. If it's a permanent card, you may put it onto the battlefield, then repeat this process.

Menace
Whenever an opponent casts a spell during your turn or an opponent casts a spell that targets a creature you control, amass Soldiers 1. (Put a +1/+1 counter on an Army you control. It's also a Soldier. If you don't control one, create an 0/0 black Soldier Army creature token first.)

Tap a creature you control: Prevent the next 2 damage that would be dealt by target creature this turn.
Tap a Reflection creature you control: Prevent all damage that would be dealt this turn by a source of your choice.

Exile all nontoken creatures. For each creature exiled this way, return that card to the battlefield under a random player's control.

({T}: Add {G} or {U}.)
Whenever Shifting Glade becomes tapped, you lose 1 life unless you control two or more basic lands.

Whenever Shifty Fink attacks, if you have more cards in hand than defending player, it gets +2/+1 until end of turn.

Flash
This spell can't be countered.
Whenever Shigurei attacks, you may activate an ability of a creature you control without paying its cost.
{1}{G}{U}: Target permanent becomes a colorless Island land until end of turn.

Shikai Revenant enters tapped.
At the beginning of your end step, if an opponent lost life this turn, you may return Shikai Revenant from your graveyard to your hand.

{T}: Add {C}.
Discard Shikai's Redoubt: Exile up to two target cards from graveyards.

Equipped creature has haste.
At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary if equipped creature is legendary. That token gains haste. Exile it at the beginning of the next end step.
Equip {2}

Create a token that's a copy of target creature.
Metamorph {2}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up and cast it at any time for its metamorph cost.)

Enchant creature you control
At the beginning of your upkeep, create a token that's a copy of enchanted creature.

{8}{U}{U}: Monstrosity 5. (If this creature isn't monstrous, put five +1/+1 counters on it and it becomes monstrous.)
When Shipway Whale becomes monstrous, target player exiles all cards in their library, then shuffles their graveyard into their library.

When Shizen, the Thousand Steps enters, draw a card, then choose a creature card name.
Creatures you control with the chosen name get +0/+1 and have hexproof.

Partner with Kasoha, Keeper of Truths (When this creature enters, target player may put Kasoha into their hand from their library, then shuffle.)
Whenever Shizura, Keeper of Traditions or another legendary creature dies, target player draws two cards and loses 2 life.

Flying
Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast your second spell each turn, draw a card.

When Shojiro, the Wavewaker enters, submerge up to eight target creatures your opponents control. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Flying
When Shomi's Savior enters, scry 3, then you gain 3 life.
Whenever you scry, put a +1/+1 counter on Shomi's Savior.