msem-instigator

The next time one or more creatures you control would die this turn, exile those cards. You may play them until the end of your next turn.

(Transform this if it's not attached to a creature. Pay {1}{R} as a sorcery to unattach it.)
Enchant creature you control
Scale Bearer's rider gets +4/+3 and has flying and haste.
Whenever Scale Bearer's rider attacks, you may pay {2}{R}. If you do, it deals damage equal to its power to target creature or planeswalker.

Whenever Scaleblight Cutthroat attacks, each opponent loses life equal to its power.
{4}{B}{B}: Scaleblight Cutthroat gets +3/+3 until end of turn.

Whenever Scavenger of the Old Bay deals combat damage to a player, draw a card.
Ride {1}{U} ({1}{U}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Scavenging Soldier has first strike as long as it's attacking.
Attain {3}{W} ({3}{W}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Scoundreleo enters the battlefield with a +1/+1 counter on it if a creature you controlled dealt combat damage to a player this turn.

Double strike
Creatures you control have trample.
Excess noncombat damage that would be dealt by sources you control to permanents an opponent controls is dealt to that player instead.

Flying, haste
Ride {1}{R} ({1}{R}: Transform this and attach it to target creature you control without a Mount. Ride only as a sorcery.)

As an additional cost to cast this spell, pay 3 life and sacrifice a creature.

Flying
Dragon spells and Adventure spells you cast cost {1} less to cast.

Counter target permanent spell. (Then exile this card. You may cast the creature later from exile.)

Until end of turn, target creature gains “When this creature is dealt damage, destroy it.” (Then exile this card. You may cast the creature later from exile.)

At the beginning of your upkeep, if six or more cards are in your graveyard, you may transform Scuttling Gnat.

Seaside Skimmer can't be blocked if you've cast a Dragon spell or Adventure spell this turn.

Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

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

Target noncreature artifact you control becomes a 0/0 artifact creature. Put three +1/+1 counters on it.

{T}: Add {C}.
{5}{R}{G}, {T}: Transform Settled Satrapy.

Exile two target cards from your graveyard. If they share a card type, draw a card. (Then exile this card. You may cast the creature later from exile.)

When Shadowlurk enters the battlefield, if a creature died this turn, put a +1/+1 counter on it.

When Shapur, the Fifth Shah enters the battlefield, exile target instant or sorcery card from your graveyard. Until end of turn, you may cast that card. If that spell would be put into a graveyard, exile it instead.
Monument {4}{R} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Flash
Unveil {3}{B}{G} ({3}{B}{G}: Transform this. Unveil only as a sorcery.)

Destroy target noncreature permanent.
Memento {5}{G}{G} (You may cast this from your graveyard for {5}{G}{G}. If you do, put it onto the battlefield transformed after it resolves. Exile it if it would leave the battlefield or not resolve.)

When Sheltered Diviner enters the battlefield, each player mills three cards.

(Transcend as a sorcery to gain that type and a +1/+1 counter.)
Ward—Discard a card.
{B}{R}: Demigod — Draw a card, then discard a card. You may have each opponent sacrifice a nonland permanent with the same mana value as the discarded card.
{4}{B}{R}: God — Create two tokens that are copies of Shi Hou's back face.