Steamveil Model enters with a +1/+1 counter on it.

Whenever Steelhorn Crusher or another artifact you control enters, artifact creatures you control gain menace until end of turn.

When Stehlian Reverend enters, put a +1/+1 counter on target creature.
Cybersoul {4}{W}

This spell costs {1} less to cast for each differently named land you control.
Stella's Journal enters with X page counters on it.
At the beginning of your end step, if you have fewer cards in hand than the number of page counters on Stella's Journal, draw cards equal to the difference.

Flying
Whenever an opponent spends mana, if it wasn't spent to cast a spell from their hand, you draw a card. This ability triggers only once each turn.

Sterling enters under the control of an opponent of your choice.
At the beginning of your upkeep, surveil 1.
Play with the top card of your library revealed.
Your opponents may play lands and cast spells from the top of your library during their turns, and they may spend mana of any type to cast spells this way.

Haste
Amity — Whenever you attack with Stitches and exactly one other creature, create a 2/2 Toy artifact creature token with defender, then tap all Toys you control. They're attacking.
At the beginning of your end step, if you didn't create a Toy this turn, transform Stitches.

Trample
Amity — Whenever you attack with Stitches, Orphaned and exactly one other creature, transform Stitches at the beginning of the next turn's upkeep.

Favored
Whenever your Champion attacks, it gets +2/+0 until end of turn.

Flying
Ward {X}, where X is the number of enchantments you control.
Whenever Stormscraper of Ketaphos deals combat damage to a player or planeswalker, create a token that's a copy of another target enchantment you control.

Equipped creature gets +1/+3 and has vigilance.
Equip {5}. This ability costs {2} less to activate if you have at least 3 life more than your starting life total.

When Stratos Sentry enters, target opponent chooses a nontoken creature they control. You integrate that creature.
As long as a creature card with power 3 or less is integrated onto Stratos Sentry, it gets +1/+0 and has flying.

Flying
When Stratus Fledgling enters, it acclimates.
Weather spells you cast cost {1} less to cast.

When Streaking Sunrise enters, scry 1, then exile the top card of your library. You may play it until the end of your next turn.

Studio Excelsior enters tapped.
{T}: Add {R}, {G}, or {W}.
{VP}{VP}{VP}{VP}, Discard Studio Excelsior: Target creature gets +2/+2 until end of turn and can't be blocked this turn.

Stunning Cascade enters tapped.
{T}: Add {U} or {R}.
{2}{U}{R}, {T}, Sacrifice Stunning Cascade: Draw a card.

{T}: Create a Treasure token.
{T}, Sacrifice a Treasure: Put a +1/+1 counter on target creature. Activate only as a sorcery.
{T}, Sacrifice two Treasures: Create a 0/0 colorless Robot artifact creature token with four +1/+1 counters on it. Activate only as a sorcery.
{3}: Untap Subsidized Market.

Haste
When Summoning Swords enters, search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.
Spellcharge 7

Flying
Favored
Whenever your Champion attacks, untap it.

When Suncaller Tortoise enters, return any number of lands you control to their owner's hand.
Landfall — When a land you control enters, Suncaller Tortoise deals 2 damage to target player. If it's a Mountain, it deals 3 damage instead. If it's a Plains, you gain life equal to the damage dealt. If it's a Swamp, that player discards a card.

Sunlit Ruins enters tapped unless you control a Swamp.
{T}: Add {G} or {W}.

Whenever you attack, Sunny Day deals X damage to target player or planeswalker, where X is the number of attacking creatures.

Sunrise Lot enters tapped.
{T}: Add {R} or {W}.
{T}, Discard another card named Sunrise Lot: Draw a card.

Sunset Slums enters tapped.
{T}: Add {W}, {U}, or {B}.
{VP}{VP}{VP}{VP}, Discard Sunset Slums: Target creature gets +3/+3 and gains trample until end of turn.

{T}: Add one mana of any color.
Amity — Whenever you attack with Sunsoaker and exactly one other creature, put a +1/+1 counter on Sunsoaker and add one mana of any color. Until end of turn, you don't lose that mana as steps and phases end.