msem-instigator

{T}: Add {C}.
{T}: Untap target legendary creature you control. Activate only once each turn.

{T}: Add {G} or {W}. You lose 1 life unless you have less life than an opponent.

{T}: Add {C}.
{T}: Put a +1/+1 counter on each legendary creature and a loyalty counter on each planeswalker that entered the battlefield under your control this turn.

{T}: Add {C}.
{T}, Sacrifice a Clue: Draw a card.

You may play Coralight Castle from your graveyard as long as seven or more cards are in your graveyard.
Coralight Castle enters the battlefield tapped.
{T}: Add {W} or {U}.
Cycling {1}{W}{U} ({1}{W}{U}, Discard this card: Draw a card.)

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

({T}: Add {B}.)
Corpsebed enters the battlefield tapped.
When Corpsebed enters the battlefield, exile up to two target cards from graveyards.

(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.

When Cosmic Contraption enters or leaves the battlefield, you may reveal a noncreature card you own from outside the game and put it into your hand.

As Coveted Tower enters the battlefield, you may pay 3 life. If you don't, it enters the battlefield tapped.
{T}: Add {G}, {U}, or {R}.

Cradle of Corruption enters the battlefield tapped.
Whenever a creature dies, put a creation counter on Cradle of Corruption.
{T}, Remove ten creation counters from Cradle of Corruption and sacrifice it: Put up to two target creature cards from graveyards onto to battlefield under your control. Activate only as a sorcery.

You can't lose the game.
At the beginning of your upkeep, put Cradle of the Sun on the bottom of your library and your life total becomes 4.

Crafted Coast enters the battlefield tapped unless another player controls a land that could produce {W} or {U}.
{T}: Add {W} or {U}.

{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.)

Cresting Bay enters the battlefield 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.

Flying
At the beginning of combat on your turn, create a 5/5 red Dragon creature token with flying and haste. That token attacks this combat if able.

You may have Crossroads Town enter the battlefield tapped. If you do, search your library for a basic land card, reveal it, then shuffle and put that card on top.
{T}: Add {C}.

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell with a creature type no creature you control has.

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 the battlefield tapped unless you control another Desert.
{T}: Add {U} or {B}.

Crumbling Necropolis enters the battlefield tapped.
{T}: Add {U}, {B}, or {R}.

({T}: Add {B} or {R}.)
Whenever Crumbling Precipice becomes tapped, you lose 1 life unless you control two or more basic lands.

Crumbling Shrine enters the battlefield tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may mill that card.)
{T}: Add {G}.
{2}{G}{G}: Crumbling Shrine becomes a Nymph creature. (This effect lasts indefinitely.)

Crumbling Vestige enters the battlefield tapped.
When Crumbling Vestige enters the battlefield, add one mana of any color.
{T}: Add {C}.

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
{1}, Discard two cards: Unlock Cryptic Fragment. If the revealed card is a basic land card, put it into your hand.