msem-instigator

When Medical Mask enters the battlefield, prevent the next 3 damage that would be dealt to any target this turn.
{4}, Sacrifice Medical Mask: Prevent the next 6 damage that would be dealt to any target this turn.

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

Memorial Ground enters the battlefield tapped.
{T}: Add {C}.
{4}, {T}, Sacrifice Memorial Ground: Return target card from your graveyard to your hand.

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.

{T}: Add {C}.
{T}, Exile Memorial of the Fallen: Shuffle your graveyard into your library.

{X}, {T}: Search your library for a creature card with mana value X or less and no creature types noted by Memorial to Sir Jasper, put it onto the battlefield, then shuffle. Note that creature's creature types. Activate only as a sorcery.

{T}: Look at the top and bottom card of your library. Put up to one on top of your library and the rest on the bottom in any order.
{2}: Mill a card.

{5}, {T}, Sacrifice Mennin Jar: Destroy target permanent. Its controller creates a 1/1 black Goblin creature token.

Activated abilities you control cost up to {1} less to activate. This effect can't reduce the amount of mana an ability costs to activate to less than one mana.

{T}: Add {C}.
Satrapies you control enter the battlefield untapped.

{T}, Sacrifice Merchant's District: Search your library for an Island or Mountain card and put it onto the battlefield tapped, then shuffle.

At the beginning of your upkeep, draw a card.
At the beginning of your end step, discard a card.

Equipped creature gets +0/+4.
Equip {2}

({T}: Add {B}.)
As Midnight Gate enters the battlefield, you may pay 1 life. If you don't, Midnight Gate enters the battlefield tapped.
Basic lands you control have “{T}: Add {B}.”

{T}: Add {C}.
{3}: Mill two cards, then return Midnight Keep from your graveyard to the battlefield tapped.

When Mighty Totem enters the battlefield, scry 1.
{1}{G}, Sacrifice Mighty Totem: Target creature gets +3/+3 until end of turn.

MiliCore Barracks enters the battlefield tapped.
{T}: Add {B} or {R}.
{B}{R}, {T}: Create a Function token with “Deathtouch.” Activate only if an opponent lost life this turn. (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Mind Palace enters the battlefield tapped.
{T}: Add {U} or {B}.
When Mind Palace enters the battlefield, you may put a loyalty counter on a planeswalker you control.

As Mind-Mute enters the battlefield, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.
{5}: Return Mind-Mute to its owner's hand.

Creatures with power greater than the number of cards in their controller's hand can't attack.

When Mindwave Rod enters the battlefield, attach it to target creature you control.
Equipped creature gets +1/+1 and has “Whenever this creature deals combat damage to a player, draw a card.”
Equip {2}

Equipped creature gets +1/+1. If it's a token, it gets +3/+3 instead.
Equip {2}

At the beginning of your upkeep, choose another planeswalker you control. You may activate that planeswalker's loyalty abilities twice this turn rather than only once.
[+2]: You may put a land card from your hand onto the battlefield. If you don't, each player draws a card.
[–2]: Exile target permanent. Return it to the battlefield under its owner's control at the beginning of the next end step.
[–7]: For each land on the battlefield, add one mana of any type that land could produce.

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
When the fourth spell of a turn is cast, you may unlock Mirror Cipher. If the revealed card is an instant or sorcery card, cast it without paying its mana cost and copy it. You may choose new targets for the copy.

Whenever equipped creature blocks or becomes blocked by a creature, you may have equipped creature become a copy of that creature until end of turn.
Equip {1}