msem-instigator

Create a token that's a copy of target creature.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

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}

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.

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.)

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.

You may look at the top card of your library any time.
{T}: Target player mills a card.

Prowess
{1}: Shifting Dweller gets +1/-1 until end of turn.

Wanderlust — Return target nonland permanent to its owner's hand. If you control four or more differently named lands, you may aetherize that permanent. (To aetherize, create a token that's a copy of it, then exile that token.)

You may tap or untap target permanent.
Draw a card.

Flying
When Shiftscale Drake enters, look at the top card of your library. You may put that card into your graveyard.

Equipped creature gets +2/+2.
Art of war — At the beginning of your end step, if equipped creature dealt damage to an opponent this turn, draw a card.
Equip {2}

Trample
When Shigurei, the Floodbringer enters, up to three target permanents become colorless Island lands.

Shimmering Seadragon gets +1/+0 and can't be blocked as long as you control a legendary creature.

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.)

Whenever you scry, put a +1/+1 counter on Shimmershell.

Kicker—Return a creature you control to its owner's hand. (You may return a creature you control to its owner's hand in addition to any other costs as you cast this spell.)
Counter target spell. If Shinrei's Ruse was kicked, draw a card.

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.

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

Whenever you cast a noncreature spell, Shiverpass Taskmage explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then you may put that card in your graveyard.)

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

Reveal the top four cards of your library and separate them into two piles. An opponent chooses one of those piles. Put that pile into your hand. Shuffle the other and up to four cards from your graveyard into your library.

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.)

Target creature gains hexproof until end of turn.
Monument {2}{U} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

{3}{U}{U}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)
When Shorecrash Octopus becomes monstrous, return target instant or sorcery card from your graveyard to your hand.