msem-instigator

Bleed {0} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
Look at target player's hand.
Draw a card.

({T}: Add {U} or {B}.)
Sodden Cavern enters tapped.

Target player mills six cards. Return each creature that shares a name with a card milled this way to its owner's hand.
Prophecy {1}{U} (Once each turn, you may exile a card with prophecy as you reveal it. When you do, you may cast it for its prophecy cost as long as it's exiled.)

When Sofia's Swashbucklers enters, you may return target card with foretell from your graveyard to your hand.

Destroy target artifact or enchantment. You gain 4 life.

Whenever Solemn Stag perseveres, put two +1/+1 counters on it. (A creature perseveres when it survives damage.)

Tap all lands target player controls and that player loses all unspent mana.

Whenever Solvent Tide attacks, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

({T}: Add {B} or {G}.)
Somber Marsh enters tapped.

When Somnambulance enters, each player conjures a card named Fatigue and puts it on top of their library. (It's a colorless sorcery that costs {2} with “Draw a card.”)
Whenever a player casts a spell named Fatigue, you may draw a card. If you do, you lose 1 life.

Create a 4/4 red Dragon creature token with flying.
Showcase {5}{U}{R} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Creatures you control get +2/+2 and gain trample until end of turn.

Put three +1/+1 counters on target creature you control. It voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)

Defender, reach
When Soothevine Elemental enters, draw a card.

Equipped creature gets +1/+0 for each instant and sorcery card in your graveyard.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Menace
Inspired — Whenever Soul Engulfer becomes untapped, each opponent loses 4 life.

Choose one—
• Soul Flame deals X damage to target nonred creature.
• Target red creature gets +X/+0 until end of turn.

When Soul Jar enters, exile target creature and each other creature with the same name as that creature until Soul Jar leaves the battlefield.

Target creature gets -3/-3 until end of turn. You gain 3 life.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
When Soul Trapper enters, tap target creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control Soul Trapper.

Soul of Misery gets +1/+1 as long as you control a Swamp.
{4}{B}: Target player discards a card. Activate only as a sorcery.

{1}, {T}, Sacrifice Soul-Synthethizer: Look at the top seven cards of your library. You may reveal a card with an activated ability from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Other Spirits you control get +1/+1.
As long as a Spirit you control has flying, Soulcleaver has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

At the beginning of each end step, if you gained life this turn, put a +1/+1 counter on a creature you control.

Flash
Other Rogues you control get +1/+1.
Rogue spells you cast have flash.