msem-instigator

[+1]: Up to one target creature gets +2/+0 until end of turn. Each player loses 1 life.
[–X]: Return target creature card with mana value X from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield.
[–7]: For each 1 life target player has less than their starting life total, create a 1/1 black Bird creature token with flying and deathtouch.

Whenever you cast a creature spell, create a 2/1 white Sand creature token with flying.
Whenever you cast an instant or sorcery spell, create a 3/1 red Sand creature token with haste.
Whenever you cast an enchantment or artifact spell, create a 2/2 blue Sand creature token with hexproof.
Whenever a land you control enters, create a 3/3 green Sand creature token.

Exile a nonland card from your graveyard: For each colored mana symbol in that card's mana cost, add one mana of that color. Activate only once each turn. (For example, if the card's mana cost is {3}{G}{G}{W}, you add {G}{G}{W}.)

When Mulchborn Behemoth enters, you may sacrifice any number of lands.
Mulchborn Behemoth gets +1/+1 for each land card in your graveyard.
{B}{G}, Sacrifice a land: Destroy target creature or land.

Look at the top three cards of your library, then put them into your graveyard or back on top of your library in any order.
Draw two cards.

Whenever a nontoken creature you control enters, if it shares no creature types with other creatures you control, draw a card.

Destroy target planeswalker. Mummy's Grin deals 2 damage to that planeswalker's controller.

Destroy target creature.

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

{T}, Pay 1 life: Add {B}.
{T}, Pay 1 life, Sacrifice Murky Peat: Search your library for a Swamp card, put it onto the battlefield tapped, then shuffle.

({T}: Add {U} or {B}.)
Whenever Murmuring Falls becomes tapped, you lose 1 life unless you control two or more basic lands.

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase. For each planeswalker you control, you may activate its loyalty abilities an additional time this turn.

At the beginning of your upkeep, germinate. Then if creatures you control have total power 10 or greater, transform Mushroom Merchant. (To germinate, put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Counter target enchantment, instant, or sorcery spell. (Then exile this card. You may cast the creature later from exile.)

Put a +1/+1 counter on up to one target creature. (Then exile this card. You may play the land later from exile.)

You may have Mutalithic Golem enter as a copy of any land on the battlefield, except it's an artifact in addition to its other types.

First strike
When Mutilated Warrior enters, you may have it deal damage to each player equal to the number of Warriors you control.

Whenever a creature you control dies, destroy target creature you don't control.

Equipped creature gets +2/+2.
Concord — Whenever equipped creature attacks, if there are four or more card types among permanents you control, create a 3/3 red Shark enchantment creature token that's tapped and attacking. Exile that token at the beginning of the next end step.
Equip {1}

[+1]: Create a tapped colorless artifact token named Conch Shell with “{T}: Add one mana of any color. Spend this mana only to cast permanent spells.”
[–1]: Reveal the top X cards of your library, where X is the number of card types among permanents you control. Put a permanent card from among them into your hand and the rest into your graveyard.
[–3]: Create two 3/3 red Shark enchantment creature tokens.

Whenever a card is put into a graveyard this turn, you may put it on the bottom of its owner's library.
Draw a card.

As Mysterious Cataract enters, you may pay 2 life. If you don't, Mysterious Cataract enters tapped.
{T}, Sacrifice Mysterious Cataract: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

{X}, Exile Mysterious Coffer: Return all nonland permanents with mana value X or less to their owner's hands.

(As you complete a condition, decode it. After all are decoded, you solve the mystery and transform this.)
When Mystery of the Crashed Craft enters, create two 1/1 red Alien creature tokens with “This creature can't block.”
{MG}—You cast an instant spell.
{MG}—You cast a sorcery spell.

(As you complete a condition, decode it. After all are decoded, you solve the mystery and transform it.)
When Mystery of the Dying Herds enters, create a 0/2 white Ox creature token.
A creature you control dies.
You have 4 or more life than your starting life total.