msem-instigator

When this creature enters, surveil 2.
This creature can't be blocked as long as it has a -1/-1 counter on it.

When Lustrebloom Diviner enters, create a Treasure token.
At the beginning of each end step, if you spent three or more colors of mana to cast spells this turn, you gain 3 life. If you spent {W}{U}{B}{R}{G}, draw a card.

Whenever Titanic Hardshell deals combat damage to a player, draw a card.
{2}{G}: Titanic Hardshell gains trample until end of turn.

Whenever equipped creature attacks, choose one —
• Tap target creature.
• Draw a card, then discard a card.
• Exile target card from a graveyard.
Equip {3}

Put a +1/+1 counter on target creature. (Then exile this card. You may cast the creature later from exile.)

Flash (You may cast this spell any time you could cast an instant.)
When Volatimancer enters, you may have target creature have base power and toughness 1/1 until end of turn.

Until end of turn, target creature gets +2/+2 and gains trample and “Whenever this creature deals combat damage to a player, investigate.” (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Flying
When Ageless Lorekeeper enters, you may discard your hand. When you do, draw three cards.

When Scrying Pool enters, scry 2.
{1}, {T}: Add one mana of any color.

This spell has flash as long as you control a creature with flash or haste.
Discard up to two cards, then draw that many cards plus one.

Whenever a creature you control dies, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Whenever you sacrifice a noncreature permanent, each opponent loses 1 life and you gain 1 life.

Destroy target land. Into the Maw of Hell deals 13 damage to target creature.

Archive 3 (As this enters, shuffle the top three cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever a source you control deals noncombat damage to a player, draw a card from the archived library.

Whenever you cast a spell you don't own, you may pay {1}{U}. If you do, put target nonland permanent on top of its owner's library.
{2}{B}: Exile the top card of target opponent's library face down. You may look at and cast that card for as long as it remains exiled, and you may spend mana as though it were mana of any type to cast that spell.

Create a token that's a copy of target artifact or enchantment you control.

Enchant creature
Enchanted creature gets +1/+2.
Whenever enchanted creature attacks, scry 1.

[+1]: Create a tapped colorless Bullet artifact token with “{T}, Sacrifice this artifact: It deals 1 damage to any target.”
[–1]: Exile target creature or planeswalker that was dealt damage this turn.
[–7]: You get an emblem with “At the beginning of each end step, you may draw X cards, where X is the amount of life your opponents lost this turn.”

{1}, {T}, Move a -1/-1 counter from another creature onto Zealous Bloodletter: Proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Sacrifice a creature. When you do, draw two cards. (Then exile this card. You may cast the creature later from exile.)

Finish Off deals 2 damage to any target. If you've drawn two or more cards this turn, it deals 3 damage instead.
Cycling {3} ({3}, Discard this card: Draw a card.)

Target creature gets +1/+0 and gains first strike until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Casualty of War deals 4 damage to target creature or planeswalker.
{2}{R}{R}, Exile Casualty of War from your graveyard: Arm up to two target creatures you control. Activate only as a sorcery. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Flash
When Remnant Spotter enters, put target permanent card from your graveyard on top of your library.

Ride {2}{W} ({2}{W}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Cycling {U} ({U}, Discard this card: Draw a card.)