msem-instigator

Creatures with power less than Seer of the Hunt's power can't block it.

Sentinel of the Highlands has hexproof as long as it's embattled. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Whenever Ser Wayver, the Broken Hour attacks, each opponent loses 2 life and you gain that much life.
When Ser Wayver dies or is countered, exile it with three time counters on it and it gains suspend. (At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast this card without paying its mana cost. It has haste.)

Flying
When Seraph of Renewal leaves the battlefield, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Flying
Whenever you cycle Seraph of the Stage or it attacks, audition for white. (Create a 1/1 Construct Actor creature token, a Scout Role giving 2/3 and vigilance, or a Cleric Role giving 2/2 and lifelink. Roles replace older ones.)
Basic landcycling {1}{W} ({1}{W}, Discard this card: Search your library for a basic land card, reveal it, and put it into your hand, then shuffle.)

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Mill two cards.
[Lore III] Return target creature card from your graveyard to your hand.

When Servant of Precursors enters, you gain 4 life and draw a card.

Flash
Menagerie — When Seven Seas Scourge enters, if there are five or more creature types among creatures you control, counter target spell with mana value 4 or less.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
When Shaman of the First Pact enters, exile up to four target creature cards from graveyards. You may cast them for as long as they remain exiled and you may spend mana as though it were mana of any type to cast them.

When Shambling Retinue dies, create a 2/2 black Zombie creature token.

(Transcend as a sorcery to gain that type and a +1/+1 counter.)
Whenever a creature enters, its controller sacrifices another creature other than Shan Jun.
{W}{B}: Demigod — Exile each opponent's graveyard. Shan Jun gains protection from each name among cards exiled this way.
{6}{W}{B}: God — Target opponent creates a 1/1 white Avatar creature token with “When this creature dies, you lose the game.”

Flash
Flying
When Sharuum, Archmagocrat enters, return to the battlefield all nonlegendary artifact cards in your graveyard that were put there from the battlefield this turn.

Flying
Glorious end — When Shattered Valkyrie dies, if it was tapped, draw a card for each creature that died this turn.
Sacrifice another creature: Shattered Valkyrie gains indestructible until end of turn.

Trample
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.)
Embattled creatures you control get +2/+0. (A creature is embattled if it has a counter on it or has a permanent you control attached to 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.

When Shepherd of Lonely Souls dies, you may return target creature card with mana value 4 or less from your graveyard to your hand.

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.

When you unveil Shining Elementalist, creatures can't block this turn.

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

{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.

Flying, vigilance

This spell costs {2} less to cast for each face-down creature you control.
Flying

Vigilance
Whenever Sibling of All Elements attacks, it gains flying until end of turn if you control a creature with flying. The same is true for first strike, double strike, deathtouch, indestructible, lifelink, menace, and trample.

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