msem-instigator

Double strike
Improve {1}{R/W} ({1}{R/W}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
At the beginning of combat on your turn, if you control three or more embattled creatures, you may search your library for an artifact, enchantment, or Angel card, reveal it, put it into your hand, then shuffle.

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.

Marin Polgek, Academy Heiress has hexproof as long as you control three or more enchantments.
{1}{W/U}{W/U}: Create a token that's a copy of target enchantment you control.

You may return a land you control to its owner's hand rather than pay this spell's mana cost.
Marinton-Ravengulch Line enters tapped.
{T}: Add {B}.

First mate—Each nonland card in your starting deck has “destroy,” “die,” “graveyard,” and/or “mill” in its printed rules text. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Deathtouch
When Marisa enters, if it was cast, you may put target permanent card from a graveyard onto the battlefield under your control.

This spell costs {2} less to cast if you've foretold a card from your hand this turn.
Whenever this creature enters or attacks, draw a card, then exile a card from your hand face down. It becomes foretold. (You can only cast it later if it has foretell.)

Enchant opponent
Whenever enchanted player searches their library, you may search your library for a card, put it into your hand, then shuffle.

Exile any number of target creatures. For each creature exiled this way, its controller creates a 3/2 green Crocodile creature token with trample.

{T}: Add {C}.
Tap five untapped Satrapies you control: Add six mana in any combination of colors.

Menace (This creature can't be blocked except by two or more creatures.)
Whenever a nontoken creature you control dies, exile the top card of your library. You may play that card until the beginning of your next end step.

Marrowskitter can't block and can't be blocked.
{3}{B}{B}: Return Marrowskitter from your graveyard to the battlefield. Create a token that's a copy of it.

Renown 1
When Marshal Jin Guiying becomes renowned, you may search your library for an artifact or enchantment card, reveal it, put it into your hand, then shuffle.

Whenever Marshback Knights becomes the target of a spell or ability an opponent controls, counter it unless they pay {3}.
{1}{U}: Marshback Knights gains flying until end of turn.

When Marshcroaker Coaching enters, create three 1/1 blue Frog creature tokens.
Frogs you control have “{T}: Target creature gains flying until end of turn.”

Whenever another creature you control dies, put a +1/+1 counter on Marshy Marauder.
When Marshy Marauder dies, create a 1/1 green Insect creature token for each counter on it.

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

Lionize {2}{U} ({2}{U}, Exile this card from your hand: Put a +1/+1 counter on target creature and it gains the following ability until end of turn. You may cast this card on a later turn from exile.)
Whenever this creature deals combat damage to a player, draw that many cards.

Choose two —
• Until end of turn if an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
• Create three 1/1 green Snake creature tokens.
• Create a 2/2 blue Bird creature token with flying.
• Create a 3/3 red Manticore creature token with haste.

Double the number of each kind of counter on target creature you control.

Discard your hand, then draw two cards for each land card discarded this way. For each opponent, Marzen's Frenzy deals damage to that player or a planeswalker they control equal to twice the number of instant or sorcery cards discarded this way.

Lifelink
If you would gain life, you may put that many +1/+1 counters on another creature you control instead.

First strike
When Masha Ritualist enters or whenever you cast a spell, if {B}{G} was spent to cast it, return target creature card with mana value 3 or less from a graveyard to the battlefield under your control. Put a +1/+1 counter on Masha Ritualist.

Whenever Masha's Vanguard deals damage to a player, you may put a creature card with mana value X or less from your hand onto the battlefield, where X is the amount of damage dealt this way.

You have hexproof.
Whenever a creature deals combat damage to you or a planeswalker you control, Mask of Shikai deals 1 damage to that creature.

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.