msem-instigator

Deception {2}{U} ({2}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Marilye deals combat damage to a player, you may search your library for an artifact card with mana value less than or equal to that amount of damage, put it onto the battlefield, then shuffle.

First strike
Whenever Martial Maestro attacks, other attacking creatures you control get +1/+0 until end of turn.

When Masterwork Archivist enters, search your library and/or command zone for a legendary card, reveal it, then put it into your hand or graveyard. If you searched your library this way, shuffle.
When Masterwork Archivist dies, you may draw a card.

Flash
Reach
Whenever Mattia enters or becomes tapped, put a +1/+1 counter on target creature you control.
{2}{G}, {T}: Target creature must be blocked this turn if able. Activate only as a sorcery.

[+1]: Add {C}. Spend this mana only to cast artifact or colorless spells.
[0 ]: Create a 1/1 colorless Construct artifact creature token.
[–2]: Look at the top six cards of your library. You may reveal an artifact or colorless card from among them and put it into your hand. Put the rest on the bottom in a random order.

Colossal 4—{5}{U}{U}{U} (You may cast this for its colossal cost to have it enter with four +1/+1 counters; or pay {5}{U}{U}{U} as a sorcery: Put four +1/+1 counters on it if it has none.)
Whenever Megalokraken enters or attacks, reveal the top X cards of your library, where X is Megalokraken's power. You may cast a noncreature spell with mana value X or less from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.

Flash
When Mennin Pack enters, each opponent loses 1 life.
When Mennin Pack dies, each opponent discards a card.

Choose one —
• Destroy target artifact.
• Metal Munch deals 1 damage to each of up to two targets.

({T}: Add {B}.)
As Midnight Gate enters, you may pay 1 life. If you don't, Midnight Gate enters tapped.
Basic lands you control have “{T}: Add {B}.”

At the beginning of combat on your turn, create a 1/1 red Cleric creature token with haste.
At the beginning of your end step, sacrifice each Cleric token you control unless you've cast an instant or sorcery spell this turn.

Flash
Flying
When Mischievous Sprite enters,you may tap or untap target permanent.

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Flying
{2}{U}{U}: Wizard — Draw a card, then discard a card. Mizuki gains “Noncreature spells you cast cost {1} less.”
{6}{U}{U}: Avatar — Draw two cards. Mizuki gains “Whenever Mizuki attacks, you may cast a noncreature spell from your hand without paying its mana cost.”

Other creatures you control get +2/+2.

{T}: You may put a creature card with mana value 2 from your hand onto the battlefield.

Codex — Leyran Alpha; Fungal Whomper; Plated Crusher; Towering Hydraffe; The Terror of Shady Cove. (As this enters, conjure its contents into a shuffled face-up additional library.)
When Mother of Monsters enters, you gain 6 life.
When Mother of Monsters dies, draw a card.

(Transform this if it's not attached to a creature. Pay {1}{W} as a sorcery to unattach it.)
Enchant creature you control
Mount of Heroes's rider gets +2/+1.
Sacrifice Mount of Heroes: Counter target spell that targets you or Mount of Heroes's rider.

({T}: Add {U} or {B}.)
Whenever Murmuring Falls becomes tapped, you lose 1 life unless you control two or more basic lands.

Trample
Whenever Muse of Summer Revelry enters or you cast a spell with power 4 or greater, choose one —
• You gain 3 life.
• Create a 2/2 green Wolf creature token.
• Draw a card.

Whenever a creature you control dies, destroy target creature you don't control.

As Mysterious Cataract enters, you may pay 2 life. If you don't, Mysterious Cataract enters tapped.
{T}, Sacrifice Mysterious Cataract: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

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.

This spell can't be countered.
Creatures you control have ward {2}. (Whenever one becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When Natural Philosopher enters, you gain 2 life for each creature you control with power 4 or greater.

As Nebula of Empty Gold enters, choose two or three colors. You lose life equal to the number of colors chosen this way.
{T}: Add one mana of any of the chosen colors.

Whenever Neon Claw Knight enters or attacks, choose one. Create a Function token with that effect. (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)
• This spell can't be countered.
• This spell costs {R} less to cast.
• If this spell would deal damage to a permanent or player, it deals that much damage plus 1 instead.

As New Divide enters, you may pay 2 life. If you don't, it enters tapped.
{T}, Sacrifice New Divide: Search your library for a basic land card, put it onto the battlefield, then shuffle.