Flash
Flying
When Sleeper Strix enters, tap up to one target creature.
You may look at an additional card each time you surveil.

Flying
Favored
Whenever another legendary nontoken creature you control dies, you may exile it. If you do, create a token that's a copy of it, except it has no name, it isn't legendary, and it is a Zombie.

When Slumbering Grove enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Spellcharge 8

Enchant land you control
Enchanted land is a 6/6 green Serpent creature with hexproof and haste. It's still a land.
When enchanted land dies, return that card to its owner's hand.

Flying, haste
At the beginning of combat on your turn, if you've cast an instant or sorcery spell with mana value 4 or greater this turn, you may return Smolderwing from your graveyard to the battlefield.

Whenever Smooth Operator deals combat damage to a player, draw a card.

Whenever one or more creatures crew Smuggler's Convoy, you may move any number of counters from those creatures to Smuggler's Convoy.
Crew 1

When Snowscryer enters, surveil 3.

When Sola enters, create a Treasure token.
{2}, Sacrifice a Treasure: You gain 3 life.
{2}, Sacrifice a Treasure: Draw a card.

Each creature you control enters with an additional +1/+1 counter on it if you cast it.
Whenever an Elemental creature you control enters, you gain life equal to its power.

Flying
Drop — When Soul Melter enters, if you didn't cast any creature spells during your last turn, each opponent loses 2 life and you gain 2 life.

When Soul-Guide Lantern enters, exile target card from a graveyard.
{T}, Sacrifice Soul-Guide Lantern: Exile each opponent's graveyard.
{1}, {T}, Sacrifice Soul-Guide Lantern: Draw a card.

Haste
At the beginning of your end step, if a creature died this turn, put a +1/+1 counter on Soundforged Tyrant.

Prevent all damage that would be dealt to Soundproof Transport by creatures blocking it.

At the beginning of your end step, if you control three or more untapped lands, up to one target nonland permanent doesn't untap during its controller's next untap step.

Flying
Nonland permanents you control have phasing.
Whenever Spacetime Seraph phases out, until your next turn, your life total can't change and you have protection from everything.

When Sparks of a Revolution enters, create a 1/1 colorless Soldier creature token. It gains haste until end of turn.
Three or more sources you controlled dealt damage this turn.
A source you controlled dealt 3 or more damage this turn.

Menace
When Speaker of Ash enters, you may sacrifice a nonland permanent or discard a card. If you do, each opponent sacrifices a nonland permanent with mana value equal to the sacrificed permanent or discarded card's mana value.

{T}: Add one mana of any color.
At the beginning of combat on your turn, if you've spent at least five mana to cast spells this turn, untap Speaker of Endless Winter and put a +1/+1 counter on it.

Whenever a Ruin you control becomes spellcharged, put a +1/+1 counter on Speaker of the Forebears.
Sacrifice Speaker of the Forebears: Add an amount of {R} equal to the number of +1/+1 counters on it.

Prowess
When Speaker of the Lightning enters, return target instant or sorcery card from your graveyard to your hand.

Whenever Spear of the Sun-Crowned attacks, if you control two or more enchanted creatures, it gains lifelink until end of turn.

Whenever another creature you control enters, you may pay {X}{X}. If you do, put X +1/+1 counters on that creature.
{T}: Add one mana of any color.

Flying
Sacrifice Spellbane Sentinel: Counter target noncreature spell unless its controller pays {1}.

Flying
Drop — When Sphinx of the Soundveins enters, if you didn't cast any creature spells during your last turn, untap up to three lands.