msem-instigator

Counter target spell if it wasn't cast from a player's hand.

At the beginning of your upkeep, you may choose a color, then exile two cards of that color from your graveyard. If you do, return a creature, instant, or sorcery card of that color from your graveyard to your hand.

Destroy all creatures.
Kindle X—{X}, Exile a card with mana value X from your graveyard. ({X}, Exile a card with mana value X and this card from your graveyard: Create X 1/1 colorless Elemental creature tokens. Kindle only as a sorcery.)

Dead-Set Duo can't block.
Whenever Dead-Set Duo deals combat damage to a player, you may pay {B} and sacrifice it. If you do, they discard two cards.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Deadland Summoner dies, you may put the card it engorged into your hand. If that card is an instant or sorcery card, you may instead cast it without paying its mana cost.

Deadwood Grove enters tapped.
{T}: Add {B} or {G}.
{1}{B}{G}: Until end of turn, Deadwood Grove becomes a 2/3 black and green Horror creature with with deathtouch and “Whenever this creature attacks or blocks, torment yourself.” It's still a land. (To torment yourself, lose 3 life unless you discard a card or sacrifice a nonland permanent.)

Deathtouch
When Deadwood Terror enters from a graveyard, create two tokens that are copies of it.
{4}{B}{B}, Sacrifice a creature: Return Deadwood Terror from your graveyard to the battlefield. Activate only as a sorcery.

Destroy target creature that's not enchanted and isn't an enchantment.

Destroy four target creatures.

You can't cast this spell as long as your life total is greater than half your starting life total.
Lifelink
{1}{B}{G}, Discard Death's Widow: Destroy target nonland permanent. You lose life equal to its mana value.

Deathtouch
When Deathbed Confessor enters, if it entered from a graveyard or you cast it from a graveyard, you draw two cards and you lose 2 life.

When Deathless Hunter dies, you may put it on the bottom of its owner's library.

You may exert Deathmarked Explorer as it attacks. When you do, it gets +X/+X until end of turn, where X is 10 minus your life total. (An exerted creature won't untap during your next untap step.)
{T}, Discard a card: Draw a card. Deathmarked Explorer deals 2 damage to you.

Creatures you control have menace.

{T}: Add {C}.
{T}, Exile two cards from your graveyard: Add {W} or {B}.

Deathwind Survivor's power and toughness are each equal to the number of enchantments you control.
Whenever an enchantment you control enters, put a +1/+1 counter on target creature.

When Debaser of Truth enters, if you control three or more Horrors, each opponent discards two cards.
Other Horror creatures you control get +1/+1.

{T}: Put a flood counter on Decanter of Endless Rivers. Add {U} for each flood counter on it.

Decay deals damage to creatures in the form of -1/-1 counters.
{B}{G}: Until end of turn, target creature deals damage to creatures in the form of -1/-1 counters. Activate only if Decay is in your graveyard.

Deception can't be blocked.
{1}{U}{B}: Target creature can't be blocked this turn. Activate only if Deception is in your graveyard.

Flash
When Decisive Arcanist enters, you may cast target modal instant or sorcery card in your graveyard. Exile that card instead of putting it into your graveyard as it resolves.

Whenever another creature you control enters, you may change Declan, Wayward Squire's base power and toughness to that creature's power and toughness until end of turn.

Indestructible (Damage and effects that say “destroy” don't destroy this creature.)
Whenever Declare, the Mother Bear deals combat damage to a player, put a +1/+1 counter on it.

Counter target creature spell, planeswalker spell, or activated ability.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever a player activates an ability of an artifact, creature, or land, if it isn't a mana ability, Dedicated Weaponsmith deals 2 damage to that player.