msem-instigator

Whenever you cast a spell, if it isn't your main phase, choose one. This ability triggers only once each turn.
• Put a +1/+1 counter on Master of Three Paths.
• Tap target creature.
• Master of Three Paths phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

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.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Master of Winds or another creature with flying you control enters, you may draw a card.

When Master of the Abyss enters, draw two cards, then discard a card.
{2}{U}{U}, {T}, Discard two cards: Create an X/X black Horror creature token, where X is the number of cards in your graveyard.

When Master of the Glen enters, create a 2/2 green Wolf Elemental creature token.
Elementals you control have trample.

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.

Equipment spells you cast cost {1} less to cast.
Equip abilities you activate cost {1} less.

Choose X. If X is 5 or greater, you may choose the same mode more than once.
• Each opponent discards a card.
• Each opponent sacrifices a creature.
• Each opponent loses 2 life.
• You draw a card and you lose 1 life.

When Matron of Machines dies, put a +1/+1 counter on up to one target creature.
{3}{W}, Exile Matron of Machines from your graveyard: Create two 1/1 colorless Construct artifact creature tokens. Activate only as a sorcery.

(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.

Menace
Whenever one or more creature cards leave your graveyard, put a +1/+1 counter on Mausoleum Resident. It gains lifelink until end of turn.

Flying
Whenever you cast a spell, draw a card, then put a +1/+1 counter on Maven of Perspective.

As long as you control another white creature, Mavisa's Familar has lifelink. The same is true for blue and flying, black and deathtouch, and red and trample.

Menace
Landfall — Whenever a land you control enters, Mawdryk's Elite gets +1/+0 and gains deathtouch until end of turn.

Reach
When Mawdryk's Harrier enters, look at the top six cards of your library. You may put an Elf card with lesser mana value from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Other Elves you control get +1/+1.

Whenever Mawdryk, Endrison Warden or another nontoken Elf creature you control enters, create a 1/1 green Elf Druid creature token.
{B}{G}, Sacrifice two Elves: Destroy target non-Elf creature.

When you cast this spell from anywhere other than your hand, it deals 5 damage to any target.
Trample

This spell can't be countered.
Flying, haste
Mayu, the Endless Flow gets +2/+2 for each spell you've cast this turn.

When Meadow Songstress enters, conjure three cards named Meadow Songstress and shuffle them into your main library.
Whenever a nontoken creature you control enters, if it shares a name with one or more other creatures you control, draw a card.

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.

Meandering Path enters tapped unless you control one or fewer other lands.
{T}: Add {R} or {G}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Mechanized Ideal gets +X/+Y, where X is the highest base power among other creatures you control and Y is the highest base toughness among other creatures you control.

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.

Trample
Enchantment spells and Aurashaper spells you cast cost {1} less to cast.
Whenever another enchantment you control enters, draw a card.