msem-instigator

Whenever one or more creatures deal combat damage to you, exile one of those creatures.
You may cast cards exiled with Merciless Mirror and may spend mana as though it were mana of any color to cast those spells.

Stinging Swordfish has first strike as long as it's attacking.
When Stinging Swordfish dies, create an Equipment enchantment artifact token named Fish Sword with “Equipped creature gets +3/+1,” “Equipped creature has first strike as long as it's attacking,” and equip {2}. You may attach that token to a creature you control.

Sacrifice Devoted Dancer: Target creature gains indestructible until end of turn. If it's your turn, shuffle Devoted Dancer into its owner's library.

{T}: Put a luster counter on Object of Awe.
{1}{R}, {T}: Discard up to X cards, then draw a card for each card discarded this way. X is the number of luster counters on Object of Awe.
{3}{R}: Until end of turn, Object of Awe becomes an X/X red Phoenix creature with flying, where X is the number of luster counters on Object of Awe.

Whenever another creature you control enters, you may upgrade Relitian Renegade. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Ward {2}
• Flying
• Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

When Harvest Blighter enters, create a black Aura Curse enchantment token named Rotting Away attached to target player. The token has enchant player and “Whenever a creature enters under enchanted player's control, if it has toughness 2 or greater, put a -1/-1 counter on that creature.”

When Umbersteed dies, target creature an opponent controls gets -4/-4 until end of turn.
Foreshadow {5}{B}{B} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

Flying
Ward—Pay 2 life. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays 2 life.)
Whenever Dire Harpies of Odunos or another creature with flying you control enters, each opponent loses 1 life and you gain 1 life.

Hexproof
Deploy 4 (As this enters, you may tap any number of other creatures you control with total power 4 or more.)
When Hamlet Witch enters deployed, return target card from your graveyard to your hand.

Choose a creature card name. Each player sacrifices a creature, then each player who controls a creature with the chosen name gets a poison counter.
Draw a card.

Knight spells you cast cost {1} less to cast.

Choose flying, prowess, vigilance, or ward {2}. Create a colorless Equipment artifact token with “Equipped creature has the chosen ability” and equip {2}. (Then exile this card. You may cast the creature later from exile.)

Glitch {1} (Remove one [restriction] for each time you pay the glitch cost.)
Target opponent reveals their hand. You choose a [noncreature,] nonland card [with mana value 3 or less] from among them. That player discards that card.

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.

Flash
Whenever you cast an artifact or enchantment spell, put a +1/+1 counter on Observer of Secret Paths. It can't be blocked this turn.

Activated abilities of artifacts cost {2} more to activate.

When Lotus-Scarred Luocha enters, create a 2/1 black Spirit creature token with “This creature can't block.”
Whenever a creature in Lotus-Scarred Luocha's pack dies, each opponent loses 2 life and you gain 2 life. (Two or more creatures you control with equal power are in a pack.)

Flash
You may cast cryptic spells as though they had flash. (Artifacts, enchantments, and modal spells are cryptic.)

Target attacking creature gets +1/+0 until end of turn. When that creature dies this turn, it deals damage equal to its power to defending player.

Landfall — This spell costs {2} less to cast if you had a land you control enter this turn.
Destroy target creature.

Civilized — At the beginning of your upkeep, if you control an artifact, a creature, and an enchantment, you draw a card and you lose 1 life.

Flash
Motivate 7 (When this creature enters, you may motivate target creature with less power than this by putting seven +1/+1 counters on it.)

Kicker—Sacrifice an artifact or creature. (You may sacrifice an artifact or creature in addition to any other costs as you cast this spell.)
Choose target creature you control. Put a +1/+1 counter on it if this spell was kicked. Then it deals damage equal to its power to target creature you don't control.

Trial 3 (As you cast this spell, an opponent of your choice may pay 3 life. If they don't, they fail the trial.)
When Steeple Deadeye enters, if the trial was failed, you gain 3 life and put a +1/+1 counter on Steeple Deadeye.

Shuffle your hand and graveyard into your library, then draw seven cards. You may have your life total become 10. You may cast a spell from your hand without paying its mana cost. Exile Bright Future.