msem-instigator

Creature spells you cast cost {2} less to cast.
Whenever another nontoken creature enters the battlefield under your control, it becomes a colorless Vehicle artifact with crew 1. (Tap any number of creatures you control with total power 1 or greater: That Vehicle becomes an artifact creature until end of turn.)

(Transcend as a sorcery to gain that type and a +1/+1 counter.)
When Dai Gui enters the battlefield, create a 1/1 green and blue Bird creature token with flying and “{T}: Add one mana of any color.”
{X}{X}{G}{U}: Demigod — You gain X life and you draw X cards. X can't be 0.
{X}{X}{G}{U}: God — Put up to X creature cards from your hand onto the battlefield.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
When Dancer of the Great Current enters the battlefield, tap up to one target creature. If you control two or more other creatures that are Merfolk, Wizards, or Rogues, instead return that creature to its owner's hand and put a +1/+1 counter on Dancer of the Great Current.

Pressure—{B}, Exile six cards from your graveyard. (You may cast this spell for its pressure cost if there are seven or more cards in your graveyard.)
Deathtouch
{B}, Exile six cards from your graveyard: Return Danithra Champion from your graveyard to the battlefield. Activate only during your turn.

{B}, Sacrifice another creature: Exile target card in an opponent's graveyard. You may cast that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell. Activate only as a sorcery.

Spells your opponents cast that target Danithra Muckbruiser cost {2} more to cast.
Danithra Muckbruiser gets +X/+X, where X is the number of cards in your graveyard minus seven. (If there are fewer than seven, it gets +0/+0.)

{T}, Discard a card, Sacrifice Danithra Oracle: Target creature gets -3/-3 until end of turn. Activate only as a sorcery.

Whenever Dapper Ragamuffin attacks, it gets +2/+0 until end of turn if you control another attacking Pirate.

Whenever Daring Skythief crews a Vehicle, that Vehicle gains flying until end of turn.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Cycling {2} ({2}, Discard this card: Draw a card.)

Flash
When Daughter of Tempests enters, target creature an opponent controls gets -2/-0 until end of turn.
Attain {3}{U} ({3}{U}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

When Dawson's Bouncer enters the battlefield, choose one —
• Put a +1/+1 counter on Dawson's Bouncer.
• Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Dawson's Collector can't block.
Whenever Dawson's Collector attacks, you may sacrifice another creature. If you do, create a tapped Treasure token.
Whenever you sacrifice your third permanent each turn, each opponent sacrifices a creature or planeswalker.

When Dawson's Enforcer enters the battlefield, draw a card if you sacrificed a permanent or discarded a card this turn.

Dawson's Marauder can't block.
When Dawson's Marauder attacks, it can't be blocked this turn unless defending player sacrifices an artifact.

When Dawson's Warden enters the battlefield, create a Treasure token.
As long as you control three or more artifacts, Dawson's Warden gets +2/+0 and has first strike.

{2}{G}{U}: Target creature you control voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever a creature you control phases in, draw a card.

Primal {R} (During your turn, you may cast this spell for {R} instead of playing a land.)
When Deadeye Drowner enters the battlefield, it deals 2 damage to any target.

Whenever Deceitful Soul becomes blocked by one or more creatures, it gets +2/+0 until end of turn.

Deep-Sea Terror can't attack unless seven or more cards are in your graveyard.

Defender
Sacrifice two Islands: Deepsea Denizen loses defender until end of turn.

Damage dealt by Deepwater Stinger can't be prevented.

Whenever Deluge Crab perseveres, target opponent mills three cards. (A creature perseveres when it survives damage.)

Creatures you don't control get -1/-0 as long as their controller is cursed.

{2}{U}{B}: Return Depth Charger to its owner's hand. If you do, return target creature to its owner's hand. That player discards a card.