msem-instigator

Flash
Flying
Whenever you cast a spell during an opponent's turn, create a Weapon token. When you do, you may attach it to another target creature with flying. (It's an Equipment artifact token with equip {2} and “Equipped creature gets +1/+1”.)

Flying
When Sky-Torrent Navigator enters, forebode. If you control two or more Pirates, forebode again. (To forebode, create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Skyblind Duo attacks, tap target creature defending player controls.

Flying
Cycling {U} ({U}, Discard this card: Draw a card.)

Flying
Tap two untapped creatures you control: Skymount Commander gains double strike until end of turn.

{1}{U}: Skysail Rigger voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Skysail Rigger phases in, put a flying counter on it.

Flying
Whenever an embattled creature you control deals combat damage to a player, draw a card. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Flying
When this creature enters, target creature gains flying until end of turn.
Arise {3}{W}{W} ({3}{W}{W}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)

Whenever Skysworn Savior attacks, you may return another creature you control to its owner's hand. If you do, Skysworn Savior gets +2/+2 and gains flying until end of turn.

Flying
As long as you control exactly one other creature, that creature gets +1/+1 and has flying.

Lifelink
When Slaffield Work-Hauler enters, create a 0/2 white Ox creature token for each enchantment you control.
Whenever an enchantment you control enters, Oxen you control get +1/+1 until end of turn.

Deathtouch, menace
Slayer of the Famed must be blocked each combat if able.

Identity — As long as you control at least two other creatures that share a creature type with Slicing Steer, Slicing Steer and creatures you control that share a creature type with it get +1/+0 and have menace.

Flying
When Slighted Spirit enters, detain up to two target creatures. (Until your next turn, those permanents can't attack or block and their activated abilities can't be activated.)

Ward {2}
Slippery Bunyip can't be blocked except by creatures with Adventures.

As long as there are four or more card types among cards in your graveyard, Slipstream Silencer can't be blocked.
Whenever Slipstream Silencer attacks, surveil 1.

Vanguard — Whenever a creature you control attacks alone, you may exile target instant or sorcery card from your graveyard. If you do, you may cast that spell from exile until your next turn. If that spell would be put into a graveyard, exile it instead.

Defender
Whenever Slumbering Bear is dealt damage, put a +1/+1 counter on it.
Remove a +1/+1 counter from Slumbering Bear: It can attack as though it didn't have defender this turn.

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Slums Thug gets +1/+1 and has menace as long as you've gained life this turn.

When Smokeweaver Initiate dies, draw a card.

Whenever you discard an instant or sorcery card, you may cast it from your graveyard. (You still pay its costs.)
Spells you cast from anywhere other than your hand cost {1} less to cast.

{2}, Return a creature you control to its owner's hand: Smooth Musician gets +1/+1 and gains lifelink until end of turn.

When Snarling Devil enters, create four 1/1 black Possum Dog creature tokens.
At the beginning of each upkeep, put your choice of a +1/+1, lifelink, menace, trample, or vigilance counter on a token creature you control.

Flying
Whenever Soaring Biome attacks, create a Plains token, Island token, Swamp token, Mountain token, or Forest token. Sacrifice that land at the beginning of the next end step.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

When Sofia's Swashbucklers enters, you may return target card with foretell from your graveyard to your hand.