msem-instigator

Attacking creatures get -3/-0 until end of turn.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Scorchland Vandal attacks each combat if able.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Scourge of the Deadlands enters, if it engorged a creature card, each other player sacrifices a creature.

When Scrapgear Contraption dies, you may put a +1/+1 counter on target creature.

When Scrapyard Aberration enters, you may sacrifice another artifact. If you do, target creature gets -2/-2 until end of turn.

Cards in graveyards lose all abilities.
Cards in graveyards can't be the target of spells or abilities.

Reveal the top five cards of your library. You may put an instant or sorcery card from among them into your hand. Put the rest into your graveyard.

Reverberate {3}{R} (When you cast this spell, copy it if you paid its reverberate cost. You may choose new targets for the copy.)
Searing Pulse deals 2 damage to any target.

Seismic Strike deals damage to target creature equal to the number of Mountains you control.

{3}: Sellsword Contraption becomes the creature type of your choice until end of turn.

When Seluriel's Blessing enters, put a +1/+1 counter on each creature you control.
Creatures you control enter with an additional +1/+1 counter on them.
Creatures you control with counters on them have vigilance and indestructible.

[+1]: You gain 1 life. Put a +1/+1 counter on up to one target creature.
[–3]: Exile target creature. Its controller gains life equal to its power.
[–8]: You get an emblem with “Creatures you control get +1/+1 and have double strike and lifelink.”

Target player discards two cards. If a creature you control died this turn, that player loses 2 life.

When Sentient Contraption enters, create a 1/1 colorless Thopter artifact creature token with flying.

Soldiercycling {1}{W}, Wizardcycling {1}{U}, Zombiecycling {1}{B}, Warriorcycling {1}{R}, Elfcycling {1}{G} ({1}{G}, Discard this card: Search your library for an Elf card, reveal it, and put it into your hand, then shuffle.)
Sentinel of Latter Days is every creature type as long as it's in your library.

Equipped creature has vigilance and reach.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

When Seven Deadly Sins has seven or more sin counters on it, sacrifice it.
{B}{B}, Put a sin counter on Seven Deadly Sins: Destroy target creature. This ability costs {1} more to activate for each sin counter on Seven Deadly Sins.

Kicker {2} (You may pay an additional {2} as you cast this spell.)
Reach (This creature can block creatures with flying.)
If Shadowcreep was kicked, it enters with two +1/+1 counters on it.

Kicker {1}{R} (You may pay an additional {1}{R} as you cast this spell.)
Shal'Draen's Rage deals 1 damage to each creature. If this spell was kicked, it deals 3 damage to each creature instead.

Look at the top three cards of your library. Put one of them into your hand, one on top of your library, and one on the bottom of your library.
Reprise {1}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Each creature you control has base power and toughness X/Y, where X is the greatest base power among creatures you control and Y the greatest base toughness among creatures you control.

Prevent all combat damage that would be dealt this turn by each creature without a counter on it.

Exile target creature. Its controller gains 3 life.

{T}: Add {C}.
{2}, {T}, Sacrifice Shifting Frontiers: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Target creature you control deals damage equal to its power to target creature with flying.