msem-instigator

At the beginning of each player's upkeep, that player loses 2 life unless they sacrifice a creature.
{4}{G}: Create a 2/2 green Wolf Elemental creature token.

Kinsang Shrine enters tapped.
{T}: Add {B} or {G}.
{B/G}, {T}, Sacrifice Kinsang Shrine: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Kuyen, Moon Spirit can't attack or block unless there are ten or more cards in your graveyard.
At the beginning of each opponent's end step, create two Food tokens. Then you may pay 3 life. If you do, surveil 3, then draw two cards.
When Kuyen dies or is put into exile from the battlefield, you may put her into her owner's library third from the top.

When Lady Ilyrana Jhalach enters, create two 1/1 black and green Elf Warrior creature tokens with reach.
{G}, Tap an untapped Elf you control: Target Elf creature gets +2/+2 until end of turn.
{1}{B}, Tap two untapped Elves you control: Target non-Elf creature gets -2/-2 until end of turn.

When Laiyru Lumberjacks dies, mill four cards, then return a land card from your graveyard to your hand.

When Landbound Ritualist enters, you may put a land card from your hand or graveyard onto the battlefield tapped.

{T}: Exile two target creature and/or land cards from a graveyard. Create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
{B}{G}, Sacrifice two Vials: Sacrifice Leticia Petrine, then return her to the battlefield transformed under her owner's control.

Return up to one target permanent or Revelation card from your graveyard to your hand.
Coalesce {5}{B}{G} (You may cast this from your graveyard for {5}{B}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

When Life from Death enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
Whenever a nontoken creature you control dies, create a 1/1 green Saproling creature token.

At the beginning of your upkeep, surveil 1.
As an additional cost to cast a spell, you may exile two cards from your graveyard. If you do, that spell costs {1} less to cast.

{T}, Mill a card: Add {B} or {G}.
Once each turn, when a creature you control dies or a creature card is put into your graveyard from anywhere other than the battlefield, each opponent loses 1 life.

As an additional cost to cast this spell, exile any number of other cards from your graveyard that have three or more card types among them.
Deathtouch
You may cast Lucid Dweller from your graveyard.

Flying, vigilance
Exile a creature card from your graveyard: Maligned Scavenger gets +1/+1 until end of turn.

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 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.

Creatures you control lose poisonous and can't have or gain poisonous.
Snakes you control deal damage to players in the form of poison counters.

Whenever Mawdryk, Endrison Warden or another nontoken Elf creature you control enters, create a 1/1 green Elf Druid creature token.
{B}{G}, Sacrifice two Elves: Destroy target non-Elf creature.

When Mire Sculptor enters, mill three cards.
Whenever you sacrifice a permanent, you may pay {2}. If you do, return target permanent card from your graveyard to your hand.

[+2]: Create a Vial token. (It's an artifact with “1, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
[–3]: Sacrifice another nonland permanent. If you do, destroy target nonland permanent.
[–9]: You get an emblem with “At the beginning of your end step, create Fallen One, a legendary 6/6 black Faerie Angel Avatar creature token with flying.”

({T}: Add {B} or {G}.)
Mossy Shrine enters tapped unless you control two or more basic lands.

Whenever you sacrifice a permanent, you may put a -1/-1 counter on target creature.

Whenever another nontoken creature you control enters, you may exile a number of cards from your graveyard equal to its mana value. If you do, create a token that's a copy of it, except the token isn't legendary if the creature is legendary.
{1}{B/G}: Look at the top card of your library. You may put that card into your graveyard.

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.

{1}{G}: Night's Guard gets +2/+2 until end of turn. Activate only once each turn.

At the beginning of your upkeep, if Nightmare Riders is in your graveyard, you may mill two cards.