msem-instigator

When Masha's Lightbound becomes tapped for the first time each turn, untap Masha's Lightbound and each other creature you control.
{W}, {T}: Exile target card from a graveyard.

Masked Impersonator can't be blocked.
Art of war — At the beginning of your end step, if Masked Impersonator dealt damage to an opponent this turn, you may have it become a copy of target creature you control except it has this ability.

Whenever another creature enters, Masquerading Bohemian becomes a copy of that creature except it's a Noble in addition to its other types and it has this ability.

Creatures you control attacking cause abilities of that creature to trigger as though it entered.
{2}{R}{W}: Target creature gains vigilance and haste until end of turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Instant and sorcery spells you cast cost {1} less to cast.
{U}, {T}, Exile three instant and/or sorcery cards from your graveyard: Draw a card.

Whenever a nonbasic nontoken land enters under an opponent's control, create a tapped colorless land token named Fading Rift with “{T}, Sacrifice this land: Add one mana of any color.”

You can't cast more than one spell each turn.
Whenever you cast a spell, draw a card.

Whenever an artifact you control enters, Master of Munitions deals 1 damage to each opponent.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, you may switch Master of Tranquility's power and toughness until end of turn.

Enchant creature
Enchanted creature gets +1/+1.
{W}: Enchanted creature gains vigilance until end of turn.
{1}{W}: Enchanted creature gains first strike until end of turn.

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever one or more creatures you control survive damage, add a quest counter.
You may put a creature card with mana value 2 or less from your hand onto the battlefield.
Put two +1/+1 counters on target creature you control.
Choose target creature you control. You draw cards equal to half that creature's power, rounded down.

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.

When Mausoleum Rite enters, each player mills four cards.
{2}{B}, Exile a creature card from your graveyard: 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.”)

When Mausoleum Suffragan enters, create a white and black Aura enchantment token named Pale Shroud attached to target creature. The token has enchant creature and “Enchanted creature gets +1/+1 and has lifelink.”
Whenever an artifact or enchantment you control enters, each opponent loses 1 life.

When Maven of Fear enters, mill two cards.
Maven of Fear gets +2/+1 and has menace as long as six or more cards are in your graveyard.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)

Enchant creature you control
Whenever enchanted creature attacks, mill three cards.
When enchanted creature leaves the battlefield, create an X/X green Spirit creature token, where X is equal to the number of card types among cards in your graveyard.

Gain control of target creature with power X or less.

Artifact vision (Whenever this or another artifact you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Mechanomind Researcher envisions an artifact card, put a +1/+1 counter on it.

Equipped creature gets +1/+1.
Whenever equipped creature becomes the target of a spell, you gain 3 life.
Equip {4}

Codex — Unraveling; Unraveling; Unrelenting; Unrelenting; Mindrip; Swipe Secrets. (As this enters, conjure its contents into a shuffled face-up additional library.)
Flash
When Mei's Collection enters, draw a card from its codex.

Destroy target artifact.
Catalyze. (The next spell you cast this turn costs {1} less to cast.)

Choose one —
• Exile target player's graveyard.
• Target player sacrifices a creature.

Rapport — Whenever Memorial of Forgotten Heroes and at least one other creature you control become tapped, put a +1/+1 counter on one of those creatures.
{T}, Tap an untapped creature you control: Add one mana of any color.

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