msem-instigator

At the beginning of combat on your turn, put a +1/+1 counter on Crosswind Cutter if it's a creature.
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.)

Target player sacrifices a creature unless they discard a creature card.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

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

Up to one target creature you control has base power 4 until end of turn. (Then exile this card. You may play the land later from exile.)

{1}{B}, Discard Crusher Claw: Target creature gains winnow until end of turn. (Damage dealt to it also causes its controller to lose that much life.)

Choose one —
• Destroy target artifact.
• Crushing Grip deals 2 damage to any target.

Enchant player
Whenever one or more creatures you control die, enchanted player loses 1 life and you gain 1 life.

Search your library for a card, exile it face down, then shuffle. For as long as that card remains exiled, you may cast it. It costs {2} more to cast this way if you don't control a legendary creature as you cast that spell.

{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.)

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.)

You gain 3 life. Choose one —
• You gain 3 life.
• Draw a card.

Distribute two -1/-1 counters among one or two target creatures.

{T}: Add {C}.
Whenever Cunning Chanter becomes tapped, each opponent mills a card.

Foretell {B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Up to one target creature gets -1/-1 until end of turn. Put a +1/+1 counter on up to one target creature.

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.

Flying
Whenever one or more counters are put on a creature you control, Curio Siren gets +1/+0 until end of turn.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Curious Cubs has first strike as long as its attacking.
When Curious Cubs has three or more +1/+1 counters on it, remove them all and transform it.

(As this Discovery enters and after your draw step, add a progress counter. Stop after you've discovered.)
I, II — Create a tapped Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Discovery — {2}, Sacrifice an artifact: Draw a card.

Whenever Current Shaper perseveres, it deals 1 damage to each opponent. (A creature perseveres when it survives damage.)

Enchant opponent
When Curse of Bleeding enters the battlefield, enchanted player loses 2 life.
Enchanted player can't gain life.

Enchant opponent
Whenever a creature enters the battlefield under enchanted player's control, that player loses 1 life and you gain 1 life.

Create a 2/2 colorless Spirit creature token.
When inscribed creature dies, create a 2/2 colorless Spirit creature token.
Inscribe {2}{B}{B} ({2}{B}{B}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Enchant opponent
Creatures enchanted player control lose hexproof and indestructible and can't have or gain hexproof or indestructible.

Equipped creature gets +2/+1.
When equipped creature deals combat damage to an opponent, you may sacrifice Cursebreaker Hammer. If you do, destroy target artifact or enchantment that player controls.
Equip {2}

Counter target spell with mana value 3 or less.