msem-instigator

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

Haste
Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Spend only mana produced by artifacts to cast Dawson's Jetslicer.

When Dawson's Loot enters the battlefield, mill two cards, then draw a card.
{1}, {T}, Sacrifice Dawson's Loot: Add one mana of any color.

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.

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

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

Search target opponent's library for a card and exile it, then do the same for their hand and graveyard. That player shuffles. You may cast spells exiled this way for as long as they remain exiled, and you may spend mana as though it were mana of any color to do so.

Up to three target creatures can't block this turn.
Menagerie — If there are five or more creature types among creatures you control, exile the top three cards of your library. You may play one of those cards until the end of your next turn.

Whenever you draw your second card each turn, create a 1/1 blue Tentacle creature token.
{3}{G}, Sacrifice two creatures: You gain 1 life and draw a card. Activate only during your turn.

{4}{B}: Depthlight Beacon gets +1/+1 and gains lifelink until end of turn.
Cycling {2/B} ({2/B}, Discard this card: Draw a card.)

When Depthlight Brute enters the battlefield, if you control three or more artifacts, each opponent loses 3 life and you gain 3 life.

Menace
Other artifact creatures you control have menace.
{2}{B}{R}: Salvage an artifact or creature card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Trample
When Depthlight Frontliner enters the battlefield, you may salvage up to one instant card and up to one sorcery card. (Exile those cards from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Deathtouch
When Depthlight Salvager enters the battlefield, you may salvage a creature card with mana value 3 or less. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Concord — When Dolphin Rider enters the battlefield, if there are four or more card types among permanents you control, you gain 5 life.

Pressure {3}{U}{B} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Destroy up to one target creature. Return all other nonland permanents to their owners' hands.

Pressure {3}{U} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Return target creature to its owner's hand. If this spell was cast for its pressure cost, put that creature into its owner's library second from the top instead.

Pressure {G} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Return target card from your graveyard to your hand. Exile Drawn to the Light.

Double strike, trample, indestructible, haste
When Dredgeline Colossus enters the battlefield, salvage up to eight noncreature, nonland cards. (You may exile them from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Creatures you control get +1/+1 until end of turn. Merfolk you control get an additional +1/+1 until end of turn.

When Dualglaive Acolyte enters the battlefield, create a green Aura enchantment token named Calamighty attached to target creature. The token has enchant creature and “Enchanted creature gets +1/+1 and can't be blocked by creatures with power 2 or less.”

When Duchess Odelia VII enters the battlefield, search your library for a nonland permanent card with mana value 1 or less, reveal it, put it into your hand, then shuffle.

Untapped creatures you control get +1/+1.
Soldiers you control have vigilance.

Vigilance
Whenever an opponent casts a spell, create a Treasure token unless that player pays {1}, then create a 1/1 white Merfolk creature token unless that player pays {1}.
{W}{U}{B}{R}{G}, {T}: Other creatures you control get +3/+3 and gain vigilance and indestructible until end of turn.