msem-instigator

Choose target creature you control, then choose two —
• Put a +1/+1 counter on it.
• It gains hexproof until end of turn.
• It can't be blocked this turn.

You may have Terracotta Legion enter as a copy of any creature with mana value 1 or less you control, except it's an artifact in addition to its other types.

When Fretport Warden enters, scry 2.

Flash
Flying
When this creature enters, it seeks valor. (Give it that Oath Aura. Fulfill it by it dealing combat damage to a player to create a 2/1 white Soldier token.)

Enchant opponent
Cards in enchanted player's graveyard lose all abilities and all names.
If enchanted player would mill one or more cards, they instead mill that many cards plus X, where X is the number of Curses attached to them.

Whenever equipped creature attacks, it gains deathtouch until end of turn.
Sacrifice Bandit's Dagger: Target player dealt damage by equipped creature this turn reveals their hand. You choose a nonland card from it. That player discards that card.
Equip {2}

Look at the top X cards of your library, where X is two plus the number of creatures you control. Exile up to two of them, then put the rest on the bottom in a random order. You may play the exiled cards until the end of your next turn.

Eureka! (At the beginning of each end step, you get a research counter if you cast a spell this turn. Then if you have eight or more research counters, remove them and create a Masterpiece token of your choice.)
Whenever an artifact you control enters, up to two target creatures get +1/+0 and haste until end of turn.

(Transform this if it's not attached to a creature. Pay {B} as a sorcery to unattach it.)
Enchant creature you control
Herald of Death's rider gets +1/+1.
Sacrifice a creature: Herald of Death's rider gets +2/+2 until end of turn.

Return target creature you control and target creature you don't control to their owners' hands.

Exile twice X cards from the top of your library. During your next turn, you may play cards exiled this way.

Whenever you gain life, Clerics you control get +1/+1 and gain trample until end of turn.

Molten Mire enters tapped unless you control a basic land.
{T}: Add {B} or {R}.

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

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
When Dancer of the Great Current enters, tap up to one target creature. If you control two or more other creatures that are Merfolk, Wizards, or Rogues, instead return that creature to its owner's hand and put a +1/+1 counter on Dancer of the Great Current.

Vigilance
Whenever Liege of Asham attacks or blocks, other attacking or blocking creatures you control get +1/+1 until end of turn.

Flash
When Crossroads Harrier enters, it deals 2 damage to target opponent or permanent an opponent controls unless that player has you draw a card.

Flying
Whenever Hoff's Scout deals combat damage to a player, you may scry 1.

Whenever a creature attacks you or a planeswalker you control, upgrade Enigmatic Protector. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Flying
• Prowess

Stampede — Whenever Nacatl Skirmisher and a creature with greater power attack, creatures you control get +1/+0 until end of turn.
{R}, Sacrifice Nacatl Skirmisher: Destroy target artifact.

Descended Countryside enters tapped.
{T}: Add {G} or {W}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Bleakrealm Moor enters tapped unless you played it from exile.
{T}: Add {B} or {R}.

Arid Causeway enters tapped unless you control another Desert.
{T}: Add {R} or {W}.

Exile target creature you control, then each other player may exile a creature they control. Each player who exiled a creature this way reveals cards from the top of their library until they reveal a creature card with mana value different from the creature they exiled, puts that card onto the battlefield, then shuffles.