Dark Horizon enters tapped.
{T}: Add {C} or {B}.
{1}, Discard Dark Horizon: Scry 2.

Return target permanent card with an activated ability from your graveyard to the battlefield. You may activate its abilities this turn as though it had haste.

When Data Weaver enters, integrate the top two cards of target opponent's library.
Once during each of your turns, you may play a card integrated onto a permanent you control, and mana of any type can be spent to cast it.

Target player discards two cards. Exile their graveyard.

First strike
Whenever Dated Mechanoid becomes tapped, another target creature you control gets +1/+1 until end of turn.

Ward {3}
Daunting Snapper can't be blocked by creatures with power 2 or less.

Exile all creatures and all cards from each player's hand. Any player may play those cards during their turn for as long as they remain exiled, and mana of any type can be spent to cast those spells.
Exile Dawn of Peace.

Flying
When Daybreak Rider enters, you may bless another target creature.

Whenever another artifact you control enters, Dazzling Illuminator can't be blocked this turn.

Ward {2}
Amity — Whenever you attack with Dazzling Performer and exactly one other creature, put a +1/+1 counter on each of those creatures. Until end of turn, they gain trample and “Whenever this creature deals combat damage to a player, draw a card.”

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token.

{6}, {T}, Sacrifice Deafening Loudspeaker: It deals 5 damage to target creature. This ability costs {1} less to activate for each attacking creature you control.

When Deathcap Guardian enters, exile any number of permanent cards from your graveyard. When you do, put X +1/+1 counters on Deathcap Guardian and up to one target creature gets -X/-X until end of turn, where X is the number of cards exiled this way.

Deathtouch
{1}, {T}: Create a Treasure token.

Ward {2}
At the beginning of your upkeep, put a +1/+1 counter on Decavolt Reactor.

You may cast this spell as though it had flash by sacrificing a creature in addition to its other costs. If you do, when it enters, attach it to target creature you control.
Equipped creature gets +2/+0 and has “Whenever this creature deals combat damage to a player, that player discards a card.”
Equip—Pay 2 life.

You may choose this spell's targets at random. If you do, it costs {2} less to cast.
Return target instant or sorcery card from your graveyard to your hand.
Flashback {6}{R}

Equipped creature gets +2/+0.
Whenever equipped creature attacks, make a pledge.
Equip {3}

Enchanted creatures you control get +2/+2 until end of turn. Other creatures you control get +2/+0 until end of turn.

Deepcavern Scyllia enters with X +1/+1 counters on it.
You may cast Deepcavern Scyllia from your graveyard by paying {3}{G} and exiling X other permanent cards from your graveyard rather than paying its mana cost.

Deeplife Cavern enters tapped unless you control a Forest.
{T}: Add {U} or {B}.

Whenever Deeptreader Arcanist attacks, you may draw a card. If you do, discard a card.

Enchant creature
You control enchanted creature.
Enchanted creature has decayed.

Create a 1/1 colorless Construct artifact creature token, then put a +1/+1 counter on each Construct you control.

Whenever Defthand Infiltrator deals combat damage to a player, put a +1/+1 counter on it if it doesn't have one on it.
Defthand Infiltrator can't be blocked as long as it has a counter on it.