msem-instigator

Flying
When Sha Long enters the battlefield, each player chooses an artifact they control, then sacrifices the rest. If they don't control an artifact, they may return an artifact card from their graveyard to the battlefield. Repeat this process for creatures, enchantments, and planeswalkers.

{U}{R}{W}, Discard a card named Sha'Iv, God of Order: Sha'Iv gains indestructible and becomes a God creature in addition to its other types.
Whenever Sha'Iv enters the battlefield or attacks, choose target creature an opponent controls. Untap it, then tap each other creature that player controls. They don't untap during their controller's next untap step.

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

Trample
Shapen, Spiteful Creation must be blocked each combat if able.
The first time Shapen, Spiteful Creation would be dealt damage each turn, prevent that damage.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

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

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.)

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
Trample
{1}, Discard Shifting Brute: Add one mana of any color. Scry 1.

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.

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

Flying, lifelink
Whenever Shioki, Imperial Heir attacks, exile any number of other target nonland permanents you control, then return those cards to the battlefield under their owner's control.

{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 Shojiro, the Wavewaker enters the battlefield, 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.)

Return up to one target creature to its owner's hand. If you do, that player discards a card at random.
Coalesce {5}{U}{B} (You may cast this from your graveyard for {5}{U}{B}. If you do, put it onto the battlefield as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Whenever Shroud the World in Doom deals combat damage to an opponent, that player discards a card at random.

Create a 1/1 black Spirit creature token with flying for each creature card and Revelation card in your graveyard.
Coalesce {6}{G}{W}{U} (You may cast this from your graveyard for its coalesce cost. If you do, put it onto the battlefield as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Siege Ent can't be blocked by creatures with power 2 or less as long as it's embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Flying, vigilance
When Silksoul Celestial enters the battlefield, search your library for an enchantment or Aurashaper card, reveal it, put it into your hand, then shuffle.
When Silksoul Celestial dies, you may put an enchantment or Aurashaper card from your hand or graveyard onto the battlefield.

Desecrate (When this creature enters the battlefield, you may sacrifice an artifact or land.)
When Siltsplitter desecrates a permanent, each opponent sacrifices an artifact.

At the beginning of combat on your turn, target creature you control gains vigilance until end of turn. That creature can't be blocked this turn.

When Sire of the Wild enters the battlefield, reveal the top four cards of your library. You may put a creature card from among them onto the battlefield. Shuffle the rest into your library.

Trample
Skalnir, Ruinbringer enters the battlefield with X +1/+1 counters on it.
When Skalnir, Ruinbringer enters the battlefield, it deals damage equal to the number of +1/+1 counters on it to each creature without trample.

Skavi Behemoth can't be the target of nongreen spells or abilities from nongreen sources.

Whenever Skeigr, Skhorvall Flagship attacks, it deals 3 damage divided as you choose among one, two, or three targets.
Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Ship Vehicle becomes an artifact creature until end of turn.)

Resolute — Skerry Serpent must be blocked if able as long as its power is greater than its base power.

Menace
Whenever an opponent casts a spell, Skhorvall Behemoth gets -2/-2 until end of turn.