msem-instigator

Whenever you cast an Aura spell, nourish 1. (To nourish 1, either put a +1/+1 counter on this creature or create a 1/1 white Citizen creature token.)

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.)

When Contagious Host dies, each player loses 1 life.
Revive {2}{B} ({2}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

Flash
Whenever you draw a card during an opponent's turn, you get a glory counter. (You lose glory counters before life. A player with ten or more glory counters wins the game.)

Landfall — Whenever a land you control enters, Convoy's Companion gets +1/+1 until end of turn. If that land was a Desert, put a +1/+1 counter on it instead.

This spell can't be countered.
Coppergild Mercenary has hexproof as long as it has one or more counters on it.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Menace
Whenever a card leaves your graveyard for the first time each turn, invigorate 1. (Choose a creature with the least power among creatures you control and put a +1/+1 counter on it.)

Vigilance, trample
Whenever you draw your second card each turn, put a +1/+1 counter on Coralblade Cohort.
Cycling {G} ({G}, Discard this card: Draw a card.)

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.”

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 Mystic enters, create a white Aura enchantment token named Whale's Spirit attached to target creature. The token has enchant creature and “Enchanted creature has lifelink.”

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.

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

Rhapsody {5}{R}{R} (Pay {5}{R}{R} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
When Corrupted Guardian enters, it deals damage equal to its power to up to one target player or planeswalker.

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.

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.

Whenever one or more cards leave your graveyard, each opponent loses 1 life and you gain that much life.

Reach
Improve {1}{G/W} ({1}{G/W}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on that creature instead.

Sacrifice a creature: Each opponent loses 1 life and you gain 1 life.
Sacrifice two creatures: Draw a card.
Sacrifice three creatures: Exile target creature or planeswalker.

When Covert Reinforcement enters, exile target nonland permanent an opponent controls until Covert Reinforcement leaves the battlefield.

Flying
When Covetous Pixie dies, if you control another Angel, Demon, Faerie, or Spirit, put a -1/-1 counter on target creature an opponent controls.

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.