msem-instigator

Choose one —
• Destroy target artifact or enchantment.
• Search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.

Exile target creature or planeswalker, then exile its controller's graveyard.

Target creature gets -2/-2 until end of turn. Mill two cards.

Exile target creature. If its power is 3 or greater, return that card to the battlefield under its owner's control at the beginning of the next end step.

Mortal Realms enters tapped unless you control two or more other lands.
{T}: Add {R}.
{T}, Pay 1 life: Add {B} or {G}.

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Fabled {4}{W}{W} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

When target creature you control dies this turn, create a token that's a copy of it, except it has no mana cost.

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.)
{3}: Unlock Mortal's Conundrum. If the revealed card is black, put it into your hand. Otherwise, put it on top of your library.
At the beginning of your upkeep, if Mortal's Conundrum is unlocked, you lose 2 life.

Mosecf, the Sunseeker's Path enters tapped.
Whenever a creature you control attacks, put a creation counter on Mosecf.
{T}, Remove ten creation counters from Mosecf and sacrifice it: Creatures you control get +2/+2 and gain vigilance until end of turn. Activate only as a sorcery.

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

(Transform this if it's not attached to a creature. Pay {1}{W} as a sorcery to unattach it.)
Enchant creature you control
Mount of Heroes's rider gets +2/+1.
Sacrifice Mount of Heroes: Counter target spell that targets you or Mount of Heroes's rider.

(Transform this if it's not attached to a creature. Pay {3}{R}{R} as a sorcery to unattach it.)
Enchant creature you control
Mount of the Order's rider gets +5/+4.
{2}{R}: Target creature can't block Mount of the Order's rider this turn.

Creatures you control get +2/+2 and gain first strike until end of turn.

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control. If that creature has flying, transform Mounting Up.

Return target nonland permanent card with mana value 2 or less from your graveyard to the battlefield.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Vanishing 3 (This permanent enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a creature dies or a time counter is removed from Mourn the Lost, you may tap target creature.

Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

Target creature can't be blocked this turn.

Scry 2, then reveal the top or bottom card of your library. Creatures you control get +X/+X until end of turn, where X is that card's mana value.
Draw a card.

Flash
Enchant creature
When Moved by Instinct enters, put a +1/+1 counter on enchanted creature.
Enchanted creature has haste and trample.

[+1]: Mpumo, Who Stands Alone deals 1 damage to any target and you gain 1 life.
[–X]: Exile target creature with mana value X.
[–6]: Choose up to four permanents an opponent controls. That player chooses one, then sacrifices the rest.

Until end of turn, target creature gets +2/+2 and gains “Whenever this creature attacks, you may post a bounty on target creature.” (Put a bounty counter on that creature. It has “When it dies, each opponent draws a card” as long as it has a bounty counter on it.)

({T}: Add {U} or {B}.)
Muggy Mire enters tapped unless you control two or more basic lands.

[+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.