msem-instigator

Target opponent chooses a card type, then reveals their hand. You choose a card from it that's not of the chosen type. That player discards that card.

Equipped creature gets +2/+1.
Whenever equipped creature becomes the target of a spell or ability for the first time each turn, counter that spell or ability.
Equip {2}

Enchant creature
Enchanted creature gets +2/+2 and has “Whenever this creature attacks, tap target creature defending player controls.”

Gain control of target artifact or creature until end of turn, then untap it. It gains haste until end of turn. You may spend mana as though it were mana of any type to pay the costs of its abilities this turn.

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

Choose two —
• Destroy target artifact.
• Discard a card, then draw a card.
• Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Cradle of Corruption enters 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 the battlefield under your control. Activate only as a sorcery.

{3}, {T}: You may put an artifact card with mana value 3 or less from your hand onto the battlefield. This ability costs {1} less to activate for each other artifact you control.

This spell costs {X} less to cast, where X is 20 minus your life total.
First strike, menace, trample

Whenever Crain's Crony enters or attacks, reveal the top card of your library and put it into your hand. You lose life equal to that card's mana value.
At the beginning of each end step, if you didn't lose life this turn, you lose the game.

Prowess
When Cramming Student enters, conjure ten cards named Fatigue and shuffle them into your library. (They're colorless sorceries that cost {2} and have “Draw a card.”)
Instant and sorcery spells you cast cost {1} less to cast.

Once each turn, you may reveal a creature card as you draw it. Whenever you do, create a 1/1 green and blue Bird creature token with flying and “{T}: Add one mana of any color.”
Whenever three or more creatures you control deal combat damage to a player, untap each creature you control.

Flash
When Cranial Glass enters, exile target card from a graveyard.
{7}, {T}, Sacrifice Cranial Glass: Copy the exiled card. You may cast the copy without paying its mana cost. (A copy of a permanent spell becomes a token.)

Each player reveals their hand. Choose a creature card revealed this way. Its owner discards it.
{2}{B}{B}, Exile Cranial Violation and six other cards from your graveyard: Put target creature card from a graveyard onto the battlefield under your control. Activate only as a sorcery.

Trample, haste
All creatures able to block Crashing Mammoth do so.

As an additional cost to cast this spell, discard a nonland card.
Draw two cards.

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.

First strike
Whenever Creed, Eternal Straggler attacks, exile the top card of your library. You may play that card this turn, and that spell costs {2} less to cast.

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.

When Gillo enters, reveal the top card of your library. If it's a land card, put it onto the battlefield tapped. If it's a creature card, put it into your hand.
As long as you control five or more creatures with different names, creatures you control get +1/+1 and have trample.

When Crimson Curtain Favored enters, starting with you, each player may discard any number of cards. When each player is finished discarding, choose one —
• Crimson Curtain Favored deals damage to each player equal to the number of cards in their hand.
• Each player draws a card for each card they discarded this way.

Flying, haste
When Crimson Hellmaw enters, it deals 3 damage to any target.
Revive {5}{R}{R} ({5}{R}{R}, 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.)

Haste
{R}{R}{R}, Discard your hand, Sacrifice Crimson Knight: Draw three cards.

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.