Storm the Citadel

Until end of turn, creatures you control get +2/+2 and gain "Whenever this creature deals combat damage to a player or planeswalker, destroy target artifact or enchantment defending player controls."

Skullwinder

Deathtouch
When this creature enters, return target card from your graveyard to your hand, then choose an opponent. That player returns a card from their graveyard to their hand.

Song of Freyalise

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Until your next turn, creatures you control gain "{T}: Add one mana of any color."
III — Put a +1/+1 counter on each creature you control. Those creatures gain vigilance, trample, and indestructible until end of turn.

Spectral Procession

Create three 1/1 white Spirit creature tokens with flying.

Settle the Wreckage

Exile all attacking creatures target player controls. That player may search their library for that many basic land cards, put those cards onto the battlefield tapped, then shuffle.

Scute Swarm

Landfall — Whenever a land you control enters, create a 1/1 green Insect creature token. If you control six or more lands, create a token that's a copy of this creature instead.

Snake Pit

Whenever an opponent casts a blue or black spell, you may create a 1/1 green Snake creature token.

Spawnwrithe

Trample
Whenever this creature deals combat damage to a player, create a token that's a copy of this creature.

Soul Warden

Whenever another creature enters, you gain 1 life.

Sol Ring

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Saproling Migration

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Create two 1/1 green Saproling creature tokens. If this spell was kicked, create four of those tokens instead.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Sundering Growth

Destroy target artifact or enchantment, then populate. (Create a token that's a copy of a creature token you control.)

Spontaneous Generation

Create a 1/1 green Saproling creature token for each card in your hand.

Serra Ascendant

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
As long as you have 30 or more life, this creature gets +5/+5 and has flying.

Sporocyst

Ravenous (This creature enters with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)
Defender
Spore Chimney — When this creature enters, search your library for up to X basic land cards, put them onto the battlefield tapped, then shuffle.

Shrine of Loyal Legions

At the beginning of your upkeep and whenever you cast a white spell, put a charge counter on this artifact.
{3}, {T}, Sacrifice this artifact: Create a 1/1 colorless Phyrexian Myr artifact creature token for each charge counter on this artifact.

Seal from Existence

Ward {3} (Whenever this enchantment becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)
When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.

Starlight Spectacular

Parade! — At the beginning of combat on your turn, choose creatures you control one at a time until each creature you control has been chosen. Each of those creatures gets +1/+1 until end of turn for each creature chosen before it. (Places everyone! The first creature in line gets +0/+0.)

Shamanic Revelation

Draw a card for each creature you control.
Ferocious — You gain 4 life for each creature you control with power 4 or greater.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Storm Herd

Create X 1/1 white Pegasus creature tokens with flying, where X is your life total.

Sram's Expertise

Create three 1/1 colorless Servo artifact creature tokens.
You may cast a spell with mana value 3 or less from your hand without paying its mana cost.

Staff of Titania

Equipped creature gets +X/+X, where X is the number of Forests you control.
Whenever equipped creature attacks, create a 1/1 green Forest Dryad land creature token. (It's affected by summoning sickness.)
Equip {3}

Song of the Worldsoul

Whenever you cast a spell, populate. (Create a token that's a copy of a creature token you control.)

Sanctuary Warden

Flying
This creature enters with two shield counters on it.
Whenever this creature enters or attacks, you may remove a counter from a creature or planeswalker you control. If you do, draw a card and create a 1/1 green and white Citizen creature token.

Scatter the Seeds

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Create three 1/1 green Saproling creature tokens.

Skrelv's Hive

At the beginning of your upkeep, you lose 1 life and create a 1/1 colorless Phyrexian Mite artifact creature token with toxic 1 and "This token can't block."
Corrupted — As long as an opponent has three or more poison counters, creatures you control with toxic have lifelink.

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Scurry Oak

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on this creature, you may create a 1/1 green Squirrel creature token.

Springbloom Druid

When this creature enters, you may sacrifice a land. If you do, search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Spirited Companion

Skyshroud Claim

Search your library for up to two Forest cards, put them onto the battlefield, then shuffle.

Somberwald Beastmaster

When this creature enters, create a 2/2 green Wolf creature token, a 3/3 green Beast creature token, and a 4/4 green Beast creature token.
Creature tokens you control have deathtouch. (Any amount of damage they deal to a creature is enough to destroy it.)

Shire Shirriff

Vigilance
When this creature enters, you may sacrifice a token. When you do, exile target creature an opponent controls until this creature leaves the battlefield.

Servo Exhibition

Create two 1/1 colorless Servo artifact creature tokens.

Soltari Visionary

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever this creature deals damage to a player, destroy target enchantment that player controls.

Staff of the Storyteller

When this artifact enters, create a 1/1 white Spirit creature token with flying.
Whenever you create one or more creature tokens, put a story counter on this artifact.
{W}, {T}, Remove a story counter from this artifact: Draw a card.

Slash the Ranks

Destroy all creatures and planeswalkers except for commanders.

Spore Swarm

Create three 1/1 green Saproling creature tokens.

Sakura-Tribe Elder

Sacrifice this creature: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Secure the Wastes

Create X 1/1 white Warrior creature tokens.

Skyhunter Strike Force

Flying
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Lieutenant — As long as you control your commander, other creatures you control have melee.

Sylvan Offering

Choose an opponent. You and that player each create an X/X green Treefolk creature token.
Choose an opponent. You and that player each create X 1/1 green Elf Warrior creature tokens.

Search Party Captain

This spell costs {1} less to cast for each creature you attacked with this turn.
When this creature enters, draw a card.

Scion of Vitu-Ghazi

When this creature enters, if you cast it from your hand, create a 1/1 white Bird creature token with flying, then populate. (Create a token that's a copy of a creature token you control.)

Sanguine Evangelist

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
When this creature enters or dies, create a 1/1 black Bat creature token with flying.

Scout the Wilderness

Kicker {1}{W} (You may pay an additional {1}{W} as you cast this spell.)
Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. If this spell was kicked, create two 1/1 white Soldier creature tokens.

Stroke of Midnight

Destroy target nonland permanent. Its controller creates a 1/1 white Human creature token.

Silverwing Squadron

Flying, vigilance
Silverwing Squadron's power and toughness are each equal to the number of creatures you control.
Whenever this creature attacks, create a number of 2/2 white Knight creature tokens with vigilance equal to the number of opponents you have.

Saproling Symbiosis

You may cast this spell as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
Create a 1/1 green Saproling creature token for each creature you control.

Second Harvest

For each token you control, create a token that's a copy of that permanent.

Kamahl, Heart of Krosa

At the beginning of combat on your turn, creatures you control get +3/+3 and gain trample until end of turn.
{1}{G}: Until end of turn, target land you control becomes a 1/1 Elemental creature with vigilance, indestructible, and haste. It's still a land.
Partner (You can have two commanders if both have partner.)

Symmetry Matrix

Whenever a creature you control with power equal to its toughness enters, you may pay {1}. If you do, draw a card.

Katerina of Myra's Marvels

As Katerina of Myra's Marvels enters, choose a letter.
Whenever you cast a spell whose name begins with the chosen letter, create a white 2/2 Cat creature token with flying.
Partner (You can have two commanders if they both have partner.)

Shalai, Voice of Plenty

Flying
You, planeswalkers you control, and other creatures you control have hexproof.
{4}{G}{G}: Put a +1/+1 counter on each creature you control.

Selesnya Charm

Choose one —
• Target creature gets +2/+2 and gains trample until end of turn.
• Exile target creature with power 5 or greater.
• Create a 2/2 white Knight creature token with vigilance.

Scale Up

Until end of turn, target creature you control becomes a green Wurm with base power and toughness 6/4.
Overload {4}{G}{G} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Selfless Spirit

Flying
Sacrifice this creature: Creatures you control gain indestructible until end of turn.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Scepter of Celebration

Equipped creature gets +2/+0 and has trample.
Whenever equipped creature deals combat damage to a player, create that many 1/1 green and white Citizen creature tokens.
Equip {3}

Skyclave Apparition

When this creature enters, exile up to one target nonland, nontoken permanent you don't control with mana value 4 or less.
When this creature leaves the battlefield, the exiled card's owner creates an X/X blue Illusion creature token, where X is the mana value of the exiled card.

Skyscanner

Flying
When this creature enters, draw a card.

Sovereign Okinec Ahau

Ward {2}
Whenever Sovereign Okinec Ahau attacks, for each creature you control with power greater than that creature's base power, put a number of +1/+1 counters on that creature equal to the difference.

Secret Rendezvous

You and target opponent each draw three cards.

Single Combat

Each player chooses a creature or planeswalker they control, then sacrifices the rest. Players can't cast creature or planeswalker spells until the end of your next turn.

Selesnya Evangel

{1}, {T}, Tap an untapped creature you control: Create a 1/1 green Saproling creature token.