msem-instigator

You may have this creature enter the battlefield as a copy of any creature on the battlefield that has a -1/-1 counter on it.

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Whenever a marked creature dies, you lose 1 life and you draw a card.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Whenever Conchhorn Shinygrabber attacks, you may pay {1}. If you do, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
{W}{U}{B}{R}{G}: Conchhorn Shinygrabber gets +3/+3 and gains lifelink until end of turn.

When Condemned Cavalier enters, create a white and black Aura Curse enchantment token named Profane March attached to target player. The token has enchant player and “Whenever a creature enchanted player controls attacks, that player loses 1 life and defending player gains 1 life.”

Other Knight creatures you control get +1/+1.

Deathtouch
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

Menace
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Lifelink
Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)

When Coralight Champion enters, create a white Aura enchantment token named Hila's Favor attached to target creature. The token has enchant creature and “Enchanted creature has double strike as long as there's another Aura attached to it. Otherwise, it has first strike.”

Concord — When Coralight Communer enters, if there are four or more card types among permanents you control, draw a card.

Flash
When Coralight Lifebloom enters, create a green Aura enchantment token named Kelpcrown attached to target creature you control. The token has enchant creature and “Enchanted creature has hexproof.”

When Coralight Paladin enters, you may search your library for an artifact card, reveal it, then shuffle and put that card on top.
Concord — Whenever Coralight Paladin attacks, if there are four or more card types among permanents you control, Merfolk you control get +1/+1 until end of turn.

Vigilance
When Coralight Sentinel enters, create a white Aura enchantment token named Crab's Resolve attached to target creature. The token has enchant creature and “Enchanted creature gets +0/+2.”

Whenever you cast a white spell, creatures you control get +1/+0 until end of turn.
Whenever you cast a blue spell, draw a card, then discard a card.

Flying
When Cormoran, Raven Monarch enters, you may put target creature card with mana value 3 or less from a graveyard onto the battlefield under your control.

{T}, Remove a +1/+1 counter from a creature you control: You draw a card and you lose 1 life.

Flying
{1}{B}, {T}: Destroy target creature that was dealt damage this turn.

Whenever an opponent casts a spell, that player gets a poison counter unless they pay {1}.
As long as an opponent has five or more poison counters, Corrupted Soothsayer gets +2/+1 and has flying.

Whenever you cast a white spell, target player loses 2 life and you gain 2 life.
Whenever you cast a green spell, put a +1/+1 counter on Corrupted Warlord.

Corsair Sellsword can't block.
Whenever you foretell a card or cast a foretold spell, you may return Corsair Sellsword from your graveyard to your hand.

Erratic (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom of your library in any order.)
Whenever a creature you control enters, if you didn't cast it from your hand, target land you control becomes a 7/1 red Elemental creature with trample and haste. It's still a land.

Flying
Whenever a creature you control that isn't enchanted dies, adjudicate.
Whenever an enchanted creature you control dies, return it to the battlefield at the beginning of the next end step.

Adorned — Coven Adherent has indestructible as long as it's equipped and/or enchanted.

Resolute — Whenever Crackling Agama deals combat damage to a player, if Crackling Agama's power is greater than its base power, that player sacrifices an artifact or enchantment.

{1}{R}, Sacrifice Crackling Seaform: Counter target spell unless its controller has Crackling Seaform deal 3 damage to them.