msem-instigator

When Smuggler of the Santriza enters, you may discard a card. If you do, draw a card.

{T}: Add {C}.
{T}: Add one mana of any color. You can't spend this to cast spells from your hand.

Equipped creature gets +1/+1.
Whenever equipped creature attacks, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Equip {2}

When Snagged Truck enters, investigate three times. (Create three colorless Clue artifact tokens with “{2}, Sacrifice this: Draw a card.”)
Snagged Truck can't attack or block as long as you control a Clue.
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.)

Enchant creature
Enchanted creature has poisonous 3. (Whenever that creature deals combat damage to a player, that player gets three poison counters.)

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.

Flash
Wither (This deals damage to creatures in the form of -1/-1 counters.)

Sneaking Capuchin can't be blocked except by creatures with defender.
{U}: Counter target spell or ability that targets Sneaking Capuchin.

Creatures with power less than Sneaking Peak's power can't block it.
At the beginning of your end step, if Sneaking Peak didn't attack this turn, put a +1/+1 counter on it.

Snow Drift enters tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may put that card into your graveyard.)
{T}: Add {U}.
{4}{U}: Snow Drift becomes an Elemental creature. (This effect lasts indefinitely.)

At the beginning of your end step, you may put a progress counter on Snowclearer.
[PROGRESS 1-2] Sacrifice Snowclearer: Add {C}.
[PROGRESS 3+] Sacrifice Snowclearer: Add two mana of any one color.

Enchant artifact or creature
Enchanted permanent doesn't untap during its controller's untap step.
Whenever you make first contact, scry 1. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

You may have Snowfield Doppelganger enter as a copy of any creature on the battlefield, except it has “While a player is choosing targets as part of casting a spell, that player must choose at least one other creature that shares a name with this creature if able.”

Prowess
When Snowline Ascetic enters, you may put target instant or sorcery card from your graveyard on top of your library.

Snowy Misthorn can block creatures with distorted as though it was tapped.

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.)

{T}: Add {C}.
{T}, Pay 1 life: Add {R} or {W}.

{T}: Add {C}. If Soaring Observatory entered this turn, add one mana of any color instead.
Tap three differently named untapped Academies you control: Add three mana in any combination of colors.

Flash
Flying
Whenever this creature enters or you cast a spell during an opponent's turn, you may exile target non-Cat permanent you control, then return that permanent to the battlefield tapped under its owner's control.

({T}: Add {G} or {U}.)
Soaring Rainforest enters tapped.
{1}, {T}: Add {G}{G} or {U}{U}.

Flying

Flying
When Soaring Skymage enters, mill four cards. You may return a creature card with flying from among the milled cards to your hand.

If you control seven or more creatures, you may cast Sociable Giant without paying its mana cost.
Trample

({T}: Add {U} or {B}.)
Sodden Cavern enters tapped.

Sodden Path enters tapped unless you control one or fewer other lands.
{T}: Add {G} or {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)