msem-instigator

Enchant creature
When Mantle of the Returned enters, return target creature card from your graveyard to the battlefield. It's a Zombie in addition to its other types.
Enchanted creature gets +1/+1 for each Zombie you control.

(Add a quest counter as this enters. Sacrifice after 6.)
Whenever a land you control enters, add a quest counter.
Reveal the top card of your library. If it's a land card, put it into your hand. Otherwise, you may put it into your graveyard.
Until end of turn, creatures you control get +5/+5 and gain vigilance, trample, and haste.
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This spell costs {1} less to cast for each differently named creature you control.
Whenever a creature you control enters, if it has a different name than each other creature you control and card in your graveyard, draw a card.

When Marauder's Broadsword enters, you may pay {1}. If you do, create a 1/1 white Soldier creature token and attach Marauder's Broadsword to it.
Equipped creature gets +2/+0.
Equip {2}

When Marauding Goliath becomes blocked by a creature with power 1 or less, sacrifice it at end of combat.

Civilized — When Marble Row Healer enters, if you control an artifact, a creature, and an enchantment, you gain 4 life.

Choose X. You may choose the same mode more than once. Create a creature token for each of the chosen characteristics.
• 1/1 white Bird with flying.
• 1/3 blue Turtle.
• 1/1 black Chipmunk with lifelink.
• 1/1 red Rabbit with haste.
• 2/1 green Squirrel with reach.

Enchant creature
Enchanted creature gets +1/+1.
When enchanted creature dies, return another target creature card from your graveyard to your hand.

Flying, lifelink
Your opponents can't search libraries.
{B}, Pay 2 life, Discard a card: Search your library for a card, then shuffle and put that card on top.

Improve {1}{W} ({1}{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.)
Prevent all combat damage that would be dealt to attacking embattled creatures you control. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

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.

[+1]: Exile up to one target tapped creature.
[–2]: Create a 4/4 white Angel creature token with flying.
[–3]: Destroy all creatures. You gain 1 life for each creature destroyed this way.
[–7]: You get an emblem with “At the beginning of each end step, you gain life equal to twice the life you've lost this turn.”

Target creature's controller judges it. Then if they honored it, you gain control of that creature until end of turn. Untap it. It gains haste until end of turn. (That creature's controller honors it by putting a +1/+1 counter on it or condemns it by sacrificing it to draw a card.)

[+1]: Discard a card. If you did, draw a card.
[–2]: Create a Bullet token. Until end of turn, if a Bullet you control would deal damage, it deals that much damage plus 1 instead. (It’s an artifact with “{T}, Sacrifice this artifact: It deals 1 damage to any target.”)

Deception {2}{U}{U} ({2}{U}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
As long as it's your turn, Marilye is a 3/2 Elf Rogue creature with hexproof and indestructible.
[+1]: Tap target permanent. It doesn't untap during its controller's next untap step.
[–2]: Exile the top five cards of target opponent's library. You may cast any number of cards exiled this way with total mana value less than or equal to the amount of damage dealt to them this turn without paying their mana costs.

You may spend mana as if it was mana of any color to cast cards exiled with Marilye.
[+1]: Exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards.
[–3]: Exile target creature. You may cast that card. If you don't, return it to its owner's hand.
[–7]: Gain control of up to five target nonland permanents.

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.

Whenever Marine Delver attacks, draw a card.

{X}{U}{U}: Marine Monster can't be blocked by creatures with mana value X or less this turn.

Marinton Occultist can't block or be blocked.
Whenever one or more cards are put into a player's graveyard from their library, Marinton Occultist gets +1/+1 until end of turn.

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}.

When Marionette Phantom enters, choose one —
• Draw a card.
• Proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

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.

Whenever Maritime Thug becomes tapped, it deals 1 damage to each opponent.

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