msem-instigator

Enchant opponent
At the beginning of enchanted player's upkeep, they mill two cards.
{U}, Sacrifice Strange Tides: Shuffle up to four target cards from your graveyard into your library.

Concord — At the beginning of combat on your turn, if there are four or more card types among permanents you control, Sturdyshell Hammerclaw gets +2/+1 and gains trample until end of turn.

When Stygian Leviathan enters, target opponent loses life equal to the number of Curses attached to them and you gain that much life.

First strike, vigilance
When Subnautical Legionnaire enters, choose artifact, enchantment, or Merfolk. Exile target nonland permanent you don't control until you control no permanents of the chosen type.

Tap up to two target creatures. Those creatures don't untap during their controllers' next untap steps. Scry 1.

{2}: Other creatures you control get +1/+0 until end of turn.
Whenever Sun-Crowned Flagship attacks, each attacking creature you control gains trample until end of turn.
Crew 7 (Tap any number of creatures you control with total power 7 or greater: This Vehicle becomes an artifact creature until end of turn.)

Pressure {3}{B}{G} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
When Sunken-Eye Angler enters, mill three cards. Then if it was cast for its pressure cost, you may return a creature card from your graveyard to the battlefield.

Flash
Flying
When Sunset Herald enters, if it was cast, return to the battlefield all creature cards from your graveyard that were put there from the battlefield this turn.

Each other Rogue creature you control enters with an additional +1/+1 counter on it.
Remove a +1/+1 counter from a creature you control: That creature can't be blocked this turn.

Haste
At the beginning of combat on your turn, target creature or Vehicle you control gets +2/+0 until end of turn.

Flying
When Swooping Razorbeak enters, you may return another permanent you control to its owner's hand.

Flash
First strike
If you cast Taiyohata Champion during your declare attackers step, it enters tapped and attacking.

Flying
As Tal, Locus Sentry enters, choose a noncreature, nonland card type.
Spells of the chosen type cost {1} more to cast.

{1}, {T}: Tap target nonartifact creature.

You may play Tectonic Chateau from your graveyard as long as seven or more cards are in your graveyard.
Tectonic Chateau enters tapped.
{T}: Add {R} or {W}.
Cycling {1}{R}{W} ({1}{R}{W}, Discard this card: Draw a card.)

Discard a card: Tender Warden gets +2/+2 until end of turn. Activate only during your turn.

Choose one —
• Counter target spell unless its controller pays {4}.
• Tap up to two target creatures. They don't untap during their controller's next untap step.

Enchant nonland permanent
Enchanted permanent's activated abilities can't be activated and triggered abilities of enchanted permanent don't trigger.

Enchant opponent
Whenever enchanted player draws a card or casts a spell, put a foreshadow counter on Thalassophobia.
Remove eight foreshadow counters from Thalassophobia and sacrifice it: Create an 8/8 blue Kraken creature token.

Destroy all lands. For each land destroyed this way, its controller creates a colorless land token named Blasted Lands with “{T}: Add {C}.”

Whenever you cast an enchantment spell, you may put target creature on the bottom of its owner's library.

When The Third Breach enters, discard your hand, then draw seven cards.
Creatures you control get +3/+3, have haste, and are Horrors in addition to their other types.
At the beginning of each end step, sacrifice each creature you control.

Target creature gets +1/+3 and gains hexproof until end of turn.

Whenever a creature you control phases in, it gets +2/+2 until end of turn.

When Three Seas Squire enters, target creature or Vehicle gets +2/+1 until end of turn.