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.

Once each turn, when Smart Shopper enters or you cast a creature spell, you may create a Berry token. If three or more types of mana were spent to cast it, create two of those tokens instead.

When Smiling Sludge enters, create a Berry token.
Whenever you sacrifice a nonland permanent, target opponent loses 1 life and you gain 1 life.

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

Equipped creature gets +1/+1.
As long as equipped creature was activated this turn, it gets an additional +2/+2 and can attack as though it were untapped.
Equip {2}

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.

Haste
Amity — Whenever you attack with Solid Smog and exactly one other creature, you may pay {R}. If you do, transform Solid Smog.

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.

When Soothing Singer enters, exile target nonland permanent you don't control until Soothing Singer leaves the battlefield.
{1}{W}: Soothing Singer gets +0/+2 until end of turn.

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.

Flying
When Soul's Sunset enters, exile up to two target cards from graveyards. You gain 2 life.
Surface {4}{B}{B}

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.

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

Enchant creature
Whenever enchanted creature becomes the target of a spell or ability, put a +1/+1 counter on it and that creature deals 1 damage to each opponent. This ability triggers no more than twice each turn.