msem-instigator

{T}: Add {C}.
{1}, {T}, Sacrifice Chikyu League Arena: Put a +1/+1 counter on target creature. Activate only as a sorcery.

As an additional cost to cast this spell, sacrifice a creature.
Target creature gets -X/-X until end of turn, where X is the sacrificed creature's power.

Cast this spell only if an opponent controls two or more nonwhite creatures or you control six or more lands.
Create X 1/1 white Bird creature tokens with flying. You gain X life.

Chiseled Cliffside enters tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

As Choked Estuary enters, you may reveal an Island or Swamp card from your hand. If you don't, Choked Estuary enters tapped.
{T}: Add {U} or {B}.

Enchant creature
When Chords of Order enters, put a +1/+1 counter on enchanted creature.
Whenever enchanted creature attacks, tap up to one target creature without a +1/+1 counter on it, then untap up to one target creature with a +1/+1 counter on it.

During your opponents' turns, Chroma, the Faerie Circle has all basic land types in all zones.
Chroma, the Faerie Circle enters tapped.

Sacrifice Chromeleon: Add one mana of any color. Scry 1.

(Choose only one work as a sorcery to add its ability.)
When Chronicles of the Kitsune enters, create a 2/1 red and white Fox creature token.
{2}{W}{W}: Act I: Ascent
Creature tokens you control get +1/+1 and have flying.
{3}{W}{W}: Act II: Descent
At the beginning of your end step, if you control no creatures, create Hu Li, a legendary 4/4 white Fox Spirit creature token with flying and lifelink.

{2}, {T}, Sacrifice Chronomancer's Bauble: For each permanent with a time counter on it, you may put a time counter on that permanent or remove a time counter from it.

Equipped creature has haste.
Sacrifice Cinderblade: Equipped creature gains +2/+2 until end of turn.
Equip {1}

{1}{R}: Circus Firebreather gets +1/+0 until end of turn.

As Citadel Gates enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}, {R}, or {G}.

{T}: Add {C}.
{1}{C}{C}, {T}: Return target legendary creature to its owner's hand.

{T}: Add {C}.
{3}, {T}, Sacrifice City Gate: Put two +1/+1 counters on target creature you control that attacked this turn.

Target creature attacks or blocks this turn if able.
Forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

Whenever another creature you control enters, you gain 1 life.
{4}{W}: Return another target creature you control to its owner's hand.

Sacrifice a creature: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Cleansing Brimstone deals 2 damage to any target. If a creature or planeswalker dealt damage this way would die this turn, exile it instead.

{T}, Pay 1 life: Add {W} or {U}.
{1}, {T}, Sacrifice Cleared Vault: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Cast this spell only during your turn.
Draw a card. Then if an opponent cast a spell this turn, scry 1 and draw an additional card.

Cliffside Entrance enters tapped unless you have 15 or less life.
{T}: Add {R} or {W}.

Equipped creature has flying.
Equip {3}

When Climber's Outfit enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Equipped creature has reach.
Equip {1}

Clocktower Hideout enters tapped.
When Clocktower Hideout enters, look at the top card of your library. You may put it into your graveyard.
{T}: Add {B} or {R}.