msem-instigator

When Roseblood Hart enters, choose one —
• Destroy target artifact.
• Create a Treasure token.

When Royal Retriever enters or when a creature you control scavenges it, you may discard a card. If you do, draw a card.
Scavenge {R} ({R}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Create a 0/0 green Wurm creature token with “This creature gets +1/+1 for each permanent card in your graveyard.”
If you would draw a card, you may instead sacrifice two lands and mill two cards. If you do, return Ruchong Awakening from your graveyard to your hand.

When Russet Denmother enters, choose one —
• Destroy target enchantment.
• Create a 2/1 red and white Fox creature token.

When Sable Evangelist enters, create a 0/1 black Cultist creature token with “{1}{B}{B}, Sacrifice three Cultists: Create a 5/5 black Demon creature token.”
Cultists you control get +2/+0 and can't block.

Whenever a creature in Sage of Circular Motion's pack becomes the target of a spell, draw a card. (Two or more creatures you control with equal power are in a pack.)

Reach
When Sage of Staves enters, choose one —
• Sage of Staves deals 3 damage to target player or planeswalker.
• Put a +1/+1 counter on target creature you control.

Sage of the Jade Baton can't be blocked by creatures with toughness 2 or greater.
Inspired — Whenever Sage of the Jade Baton becomes untapped, draw a card, then discard a card.

Flash (You may cast this spell any time you could cast an instant.)
When Sanguine Muralist enters, you may have target creature's toughness become 1 until end of turn.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Search your library for up to three creature cards with different mana values 4 or less, reveal them, put them into your hand, then shuffle. If you're in a renaissance, you may put one of those cards onto the battlefield instead of into your hand.

Deathtouch
Inspired — Whenever Scar Tattooist becomes untapped, you may have target creature get -1/-1 until end of turn.

Target player reveals their hand. You choose a nonland card from it. That player discards that card. Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Scholar of the Staff can't block.
Inspired — Whenever Scholar of the Staff becomes untapped, up to one target creature can't block this turn.

Scorching Dragonfire deals 3 damage to target creature or planeswalker. If that permanent would die this turn, exile it instead.

Flying
Whenever you cast an instant or sorcery spell, Scourge of the Sun gets +1/+0 until end of turn. If you spent four or more mana to cast that spell, Scourge of the Sun gets an additional +1/+0 until end of turn.

Whenever you cast an instant or sorcery spell, put a +1/+1 counter on Scribe of the Sky Scrolls. If you spent four or more mana to cast that spell, Scribe of the Sky Scrolls gains flying until end of turn.

Scrounging Dunes enters tapped.
{T}: Add {W} or {B}.
{1}{W}{B}: Until end of turn, Scrounging Dunes becomes a Wurm creature with lifelink in addition to its other types.
Scavenge {1}{W}{B}

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Target creature or planeswalker an opponent controls phases out. If you're in a renaissance, exile it instead.

When Seeker of Far-Off Lands enters, search target opponent's library for a land card, put it onto the battlefield tapped under your control, then that player shuffles.

{T}: Add {G} or {U}. You lose 1 life unless you have less life than an opponent.

When Serum Peddler enters, you draw a card and you lose 1 life.

[+1]: Create three 1/1 white Warrior creature tokens. They gain haste.
[0]: Until end of turn, each creature and planeswalker you control becomes a 3/3 Warrior creature and gains indestructible. (Permanents don't lose loyalty while they're not a planeswalker.)
[–2]: Choose tapped or untapped. Seto San deals 3 damage to each creature with the chosen attribute.

(Choose only one work as a sorcery to add its ability.)
When Seto's Private Collection enters, creatures you control get +2/+1 until end of turn.
{1}{R}: Bloodline
Attacking creatures you control have first strike.
{2}{W}: Hope's Savior
Attacking creatures you control have lifelink.

Flying
When Sha Long enters, each player chooses an artifact they control, then sacrifices the rest. If they don't control an artifact, they may return an artifact card from their graveyard to the battlefield. Repeat this process for creatures, enchantments, and planeswalkers.

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Ward {2}
{2}{U}: Demigod — Exchange a card in your hand and a noncreature, nonland card in your graveyard.
{6}{U}: God — Exchange control of two target permanents that share a card type.