msem-instigator

Death knell — Put a trample counter on target creature you control. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)
Sacrifice a creature: Put a +1/+1 counter on Crushing Victor. Activate only as a sorcery.

When Crux Pinnacle enters, for each color, exile up to one target permanent of that color until Crux Pinnacle leaves the battlefield.
Whenever a player casts a spell, if there are five or more spells on the stack, you win the game.

Deathtouch
When Crypt Strider enters, create a 1/1 black Skeleton creature token for each creature card in your graveyard.

Flash
Deathtouch

{T}: Add {C}.
{X}: Crypt of Myriad Fates becomes a copy of target creature card with mana value X or less in your graveyard until end of turn, except it's 2/2 and a land in addition to its other types. Activate only outside of combat.

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.

Cryptic Reef enters tapped.
{T}: Add {G} or {U}.
{2}{G}{U}, {T}, Sacrifice Cryptic Reef: Draw a card.

When Cryptic Sentinel enters, attach any number of target Auras you control to Cryptic Sentinel.
{G}{W}, Sacrifice an Aura: Tap Cryptic Sentinel. It gains indestructible until end of turn.

When Cryptic Waypoint enters, create a 1/1 blue Scout creature token.
{T}: Add {G}, {U}, or {R}.

{2}{G}: Cryptozoologist voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Cryptozoologist phases in, you may put a creature card from your hand onto the battlefield until Cryptozoologist leaves the battlefield. (It returns to your hand if it's still on the battlefield.)

Whenever you sacrifice a permanent, scry 1.
{1}, Sacrifice a nonland permanent: You gain 1 life.

Put three +1/+1 counters on target land. It becomes a 0/0 colorless Elemental creature with haste that's still a land.
Orchestrate—Sacrifice a land. (You may exile this card from your hand anytime you could cast a sorcery for its orchestrate cost. When you next resolve a spell, you may cast this from exile without paying its mana cost.)

Crystal Garden enters tapped.
{T}: Add one mana of any color. You can't spend this mana to cast a creature spell.

{T}: Add {C}.
{T}, Pay 1 life: Add {U} or {B}.

Target player sacrifices a creature.
{2}{G}, Exile Crystal Puncture from your graveyard: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

When Crystal Vision Abomination enters, create a 1/1 blue Elemental creature token with flying.
Whenever an Elemental you control attacks, that creature gets +1/+0 and first strike until end of turn.

Flying
Sacrifice Crystalcatcher: Counter target creature spell unless its controller pays {1}.

When Crystalline Golem enters, choose a color. You gain 1 life for each permanent of that color you control.

Reflections you control get +2/+2 until end of turn. Other creatures you control get +1/+1 until end of turn.

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
When Cuff Down enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Double strike
{3}{W}: Arm target creature you control. Activate only as a sorcery. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Flash
When Culi-Sae Mesmer enters, return all permanents attached to target permanent or player to their owners' hands.

At the beginning of combat on your turn, target embattled creature you control gets +1/+1 and gains vigilance and indestructible until end of turn. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Flash (You may cast this spell any time you could cast an instant.)
When Culi-Sae Transfigurer enters, switch target creature's power and toughness until end of turn.

Equipped creature gets +2/+1 and has menace.
Whenever equipped creature deals combat damage to a player, they sacrifice two permanents.
Equip—{2}, Sacrifice a creature.