msem-instigator

Creatures your opponents control attack each turn if able.
Blocking creatures you control get +4/+0.
{W}: Untap Masha, Hero of Pelastrov.

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Masked Lancer has first strike as long as it's attacking.
Whenever Masked Lancer mentors a creature, that creature gains first strike until end of turn.

Flying
When Masked Stalker enters, target player discards a card.

Whenever one or more cards are put into exile from anywhere, target opponent loses 1 life.
Whenever one or more creatures you control deal combat damage to a player, you may pay 2 life. If you do, purge. (Exile two cards that share a type from graveyards. If you do, draw a card.)

When Master Chef enters, create a 0/1 green Plant creature token.
Sacrifice a Plant: You gain 3 life.

When Master Negotiator enters, you may gain control of target nonland permanent an opponent controls with mana value 2 or less. If you do, its controller may draw a card. Otherwise, you draw a card.

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Master of Ancient Ways mentors a creature, that creature gains double strike until end of turn.

You may choose not to untap Master of Minds during your untap step.
{T}: Gain control of target creature with mana value X or less for as long as Master of Minds remains tapped, where X is the number of Islands you control.

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.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | When you next cast an instant or sorcery spell this turn, copy it. You may choose new targets for the copy.
3 | When you cast your next creature spell this turn, copy it.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever an experience ability puts a +1/+1 counter on a creature you control, put a +1/+1 counter on that creature.

Poisonous 3 (Whenever this creature deals combat damage to a player, that player gets three poison counters.)
At the beginning of your upkeep, if an opponent is poisoned, you may have Mautakesh Strangler fight target creature you don't control.

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.

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.

Landfall — Whenever a land you control enters, add {G}.
{3}{G}: Target creature you control gets +2/+2 until end of turn.

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
Recursive — As long as Mayar, Nullcrowned is a Curse, they have all nonrecursive abilities of other Curses and creatures with breach you control.
Pay 3 life: Target enchantment creature gains haste and menace until end of 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.

Shuffle the cards from your hand into your library, then draw that many cards.
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.

[+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.

I, II — Put a +1/+1 counter on target creature you control.
Discovery — Creatures you control with +1/+1 counters on them have lifelink.

At the beginning of combat on your turn, if you cast an enchantment spell, an instant spell, and a sorcery spell this turn, create two 3/3 red Shark enchantment creature tokens. You may have any number of those tokens gain haste. If you do, sacrifice the tokens you chose at end of combat.

{W}{B}, Pay X life: Return target creature card with mana value X from your graveyard to the battlefield with a finality counter on it. Activate only as a sorcery and only once each turn.
{W}{B}, Pay 3 life: Return Mehr's Last Captain from your graveyard to the battlefield with a finality counter on it.

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Whenever a marked creature dies, put a +1/+1 counter on Mei's Collector.

[+1]: Draw a card unless an opponent discards a card.
[–3]: Gain control of target creature until the end of your next turn.
[–6]: Choose up to four cards in graveyards. You may play those cards without paying their mana costs.