msem-instigator

Create a 1/1 white Soldier creature token with vigilance.
At the beginning of combat on your turn, you may pay {2}{W}. If you do, creatures you control get +1/+1 until end of turn.

Civilized — This spell costs {1} less to cast if you control an artifact, a creature, and an enchantment.
Counter target spell.

Enchant creature or planeswalker
As Consumed by Fashion enters, put two loyalty counters on enchanted permanent.
You control enchanted permanent. It's an Okus planeswalker with “+1: Scry 1” and “-3: Draw a card” and loses all other card types and abilities.

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.

Level experience (Whenever this creature attacks, if it has fewer than three level counters on it, put a level counter on it.)
When Copperhide Calf has three or more level counters on it, remove them all and transform it. [2/2]
[level 1-3] Prevent the first 1 damage that would be dealt to Copperhide Calf each turn. [3/3]

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.)

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

Deathtouch
When Corpsecaster Mage enters, if you cast it, target creature card in your graveyard gains arise until end of turn. Its arise cost is equal to its mana cost. (Exile that card from your graveyard and pay its arise cost: Create a token that's a copy of it except it's a black Zombie in addition to its other types, has no mana cost, and can't block. Arise only as a sorcery.)

(Transform this if it's not attached to a creature. Pay {3}{B} as a sorcery to unattach it.)
Enchant creature you control
Corrupted Mount's rider gets +5/+4 and can't block.

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.

When Cosmonaut Pioneer enters or leaves the battlefield, choose one—
• Scry 1, then draw a card.
• Create a 3/3 green Alien creature token with trample.
• You gain 5 life.

Whenever another creature with power 2 or less you control enters for the first time each turn, you may pay {W}. If you do, draw a card.

As an additional cost to cast this spell, discard a card.
Draw two cards. The next card you foretell this turn costs {0} to foretell.

Wanderlust — This spell costs {2} less to cast as long as you control four or more differently named lands.
Crackle Across Kahembo deals X damage to target creature or planeswalker.

Enchant land
When Cradle of Civilization enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Enchanted land has “{T}: Add one mana of any color.”

Bloodprice—Reappropriate red. (You may cast this spell by sacrificing a creature and exiling two red cards from your hand and/or graveyard.)
Haste
Whenever Creed's Desperado attacks, if defending player has more cards in hand than you, exile the top card of that player's library. You may cast it as long as you control a Warrior, and you may spend mana as though it were mana of any color to cast it.

{T}: Add {C}.
{3}, {T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

When Crescent of the Harvest Moon enters or whenever equipped creature attacks, exile up to one target card from a graveyard.
Equipped creature gets +1/+1.
{X}: Equipped creature becomes a copy of a permanent card with mana value X or less exiled with Crescent of the Harvest Moon until end of turn (even if this becomes unattached). Activate only as a sorcery.
Equip {2}

Cresting Bay enters tapped unless you control a basic Island.
{T}: Add {U}.
{2}{U}{U}: Until end of turn, Cresting Bay becomes a 3/3 blue Elemental creature with “Whenever this creature attacks, you may draw a card then discard a card.” It's still a land.

Tithe (As you cast this spell, you may tap three artifacts and/or creatures you control.)
Croakfolk Marsh-Baron enters with X +1/+1 counters on it. If its tithe was paid, it enters with twice X +1/+1 counters instead.

When Crooked Merchant dies, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Equipped creature gets +X/+X, where X is the number of cards in your graveyard.
Sacrifice a creature other than equipped creature: Equipped creature gains lifelink and indestructible until end of turn.
Equip {3}

Crumbling Aqueduct enters tapped unless you control another Desert.
{T}: Add {U} or {B}.

Each opponent discards two cards. If you control a Knight or Soldier, each opponent loses 2 life and you gain 2 life.

Assault {3}{G} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Crushclaw Pulverizer assaults, you may destroy target artifact or enchantment.