msem-instigator

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

Hexproof
Whenever one or more cards are put into your graveyard from anywhere, Creeping Hidebehind gets +1/+0 until end of turn.

Harmony — Target player mills four cards.
When Creeping Pianist enters, harmonize. (Trigger up to one harmony of one permanent you control.)

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

Whenever another creature named Crinster Sheepdog enters, nourish 1. (To nourish 1, either put a +1/+1 counter on this creature or create a 1/1 white Citizen creature token.)

{T}, Tap two other untapped creatures you control: Add two mana of any one color.

Hexproof
Whenever an enchantment you control enters, draw a card.

Reach
Scarecrow spells you cast cost {1} less to cast.

Flying
Cruel Fledgling enters with a +1/+1 counter on it if six or more cards are in your graveyard.

Whenever Cruising Schooner attacks, it gets +1/+1 until end of turn.
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Vehicle becomes an artifact creature until end of turn.)

Creatures you control get +4/+4 and gain trample until end of turn.
Coalesce {8}{G}{G} (You may cast this from your graveyard for {8}{G}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Trample

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.

Menace, haste, decayed (This can't block. When it attacks, sacrifice it at end of combat.)
At the beginning of combat on each of your turns, if you have three or more creature cards in your graveyard and haven't controlled a creature named Crypt Gnawer this turn, return Crypt Gnawer from your graveyard to the battlefield.

{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.)

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

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

Lifelink
Whenever you sacrifice a nonland permanent, you may pay {1}. If you do, you draw a card and you lose 1 life.

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
As long as an opponent has ten or more cards in their graveyard, Cunning Infiltrator gets +3/+2 and can't be blocked.

Elemental, Demon, and Spirit spells you cast cost {1} less to cast.
Whenever you cast a Elemental, Demon, or Spirit spell, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Whenever you draw your second card each turn, put a +1/+1 counter on Current Surfer.
{R}, Discard your hand, Sacrifice Current Surfer: Draw X cards, where X is its power. At the beginning of the next end step, discard your hand.

When Customs Lookout enters, each player draws a card, then discards a card.
Whenever an opponent casts a spell with the same name as a card they own in exile or in their graveyard, you may scry 2.

Haste
Whenever a creature dealt combat damage by Cutthroat Carnie this turn dies, you may have Cutthroat Carnie fight target creature.

Whenever Cutthroat Spy deals combat damage to a player, you may draw a card.

When CySec Spectre enters, you may sacrifice a creature. If you do, target opponent loses 3 life and you gain 3 life.

Flash