First strike
Landfall — Whenever a land you control enters, you may tap target creature.

Vigilance
{T}: Add {C}.
{T}: Add {C}{C}. Activate only if Steadfast Gatekeepers is a creature.
Spellcharge 3

Enchant creature
Enchanted creature gets +3/+3.
{4}{G}, Exile Steady Bass from your graveyard: Put three +1/+1 counters on target creature. Activate only as a sorcery.

Steam Colony enters tapped.
{T}: Add {U} or {R}.
{1}, Discard Steam Colony: Scry 2.

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.

Exile target creature, then return that card to the battlefield under its owner's control. When you do, pay for and choose any number.
+{W} — Distribute two +1/+1 counters among one or two creatures you control.
+{C} — Exile that creature again. Return that card to the battlefield under its owner's control at the beginning of the next end step.
+{B} — All creatures get -1/-1 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.

Create a Berry token, then sacrifice any number of Berry tokens. Target creature you control gets +1/+1 until end of turn for each Berry sacrificed this way. Then it fights target creature you don't control.

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

Exile the top two cards of target opponent's library. You may play them until the end of your next turn, and mana of any type can be spent to cast them.

Any number of creatures you control fight different creatures you don't control. Each other creature you control gets +3/+3 and gains trample 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.