msem-instigator

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

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

Flying, haste
Whenever Shimmering Dragon attacks, for each creature you control, create a tapped and attacking token that's a copy of that creature. Exile the tokens at the beginning of the end step.

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.)

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.

Flash
If one or more counters would be put on a creature you control, put that many plus one of each of those kinds of counters on that creature instead.

{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.

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.

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.)

{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.

Haste
Each creature with toughness greater than its power can't block.

Flying, vigilance

Haste
Whenever you sacrifice another permanent, put a +1/+1 counter on Shrine Razer.

If a spell or ability would cause a player to discard one or more cards, that player discards that many cards at random instead.
Whenever a player discards a card, that player loses 2 life.

Vigilance
Shuye, Forever Watching's power and toughness are each equal to the number of noncreature permanents you don't control.

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.)

Improve {1}{R} ({1}{R}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
When Siegebreaker Ogre enters, create two 1/1 red Goblin creature tokens with haste.

Deathtouch
When Siesa Tremund enters, for each player, search that player's library for a card and exile it. That player shuffles. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any type to cast those spells.

Flash
Whenever you cast Siflir, Elder Pawn or another spell, if you paid an alternate or additional cost to cast it, draw a card.
Wander {3}{U}{U} (You may cast this from the battlefield for its wander cost.)

Reach

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

Destroy target creature. It can't be regenerated.

Counter target spell.
Forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

This spell costs {1} less to cast for each poison counter your opponents have.
Poisonous 1 (Whenever this creature deals combat damage to a player, that player gets a poison counter. A player with ten or more poison counters loses the game.)
At the beginning of your end step, each opponent with seven or more poison counters loses the game.

Counter target spell. If you control a Wizard, scry 2. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)