msem-instigator

Whenever one or more cards are put into your graveyard from your library, exile one of those cards.
Whenever Colossal Hermit deals combat damage to a player, you may cast a card exiled with it without paying its mana cost.

Lifelink
Partner with Imperator Valtasius (When this creature enters, target player may put Imperator Valtasius into their hand from their library, then shuffle.)
At the beginning of your upkeep, return target Soldier card from your graveyard to your hand.

When Commander of the Cavalry enters, you may search your library for a creature card with ride, reveal it, and put it into your hand. If you do, shuffle.
{X}, {T}: Put a creature card with ride and mana value X or less from your hand onto the battlefield transformed and attached to another target creature you control without a Steed attached to it.

Adorned — Commoners' Favored gets +2/+2 as long as it's equipped and/or enchanted.

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.

Spells you cast from exile cost {1} less to cast.

{T}: Conchspear Hunter deals 1 damage to any target. Activate only if you control three or more artifacts.

At the beginning of combat on your turn, you may exile a creature card from your graveyard. Then if a card exiled with Concoquo has flying, creatures you control gain flying until end of turn. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

Ferocious — At the beginning of your first main phase, if you control a creature with power 4 or greater, add {R}.

Vigilance
Conflict Capturer gets +2/+0 as long as a permanent you controlled left the battlefield this turn.

When Conjured Shade dies, target creature you don't control gets -1/-1 until end of turn.

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.