msem-instigator

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

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}

Mirrorgate enters tapped.
When Mirrorgate enters, you choose a nonbasic land card name other than Mirrorgate, then each player chooses a color.
Lands with the chosen name are lands with “{T}: Add one mana of any of the chosen colors,” and lose all other abilities, card types, and land types.
{T}: Add one mana of any of the chosen colors.

When Miserable Portent enters, create a 1/1 black Harpy creature token with flying.
{3}{B}, Sacrifice Miserable Portent: You draw two cards and you lose 2 life.

Create a 1/1 blue Illusion creature token with “This gets +1/+1 for each other Illusion you control.”
Coalesce {6}{B} (You may cast this from your graveyard for {6}{B}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Misery Keeps Company is an Illusion in addition to its other types while it's a creature.

Players play with the top card of their libraries revealed.
[+2]: Target player mills a card. Draw a card.
[+1]: Create a 1/1 blue Illusion creature token with “This gets +1/+1 for each other Illusion you control.”
[–4]: Return target creature card from a graveyard to the battlefield under your control. It's an Illusion in addition to its other types.

Counter target noncreature spell with an odd mana value. (Zero is even.)

Glitch {2} (Remove one [restriction] for each time you pay the glitch cost.)
Create a 3/2 red creature token named Error with trample and haste. [Exile it at the beginning of the next end step.]

Foretell {3}{U}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Draw a card. If this spell was foretold, draw three cards instead.

You may play an additional land on each of your turns.
Landfall — Whenever a land you control enters, draw a card.

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever Mistress of Frost extorts a spell, you may tap target artifact or creature.

Misty Churchyard enters tapped.
{T}: Add {W}.
{1}{W}{W}: Until end of turn, Misty Churchyard becomes a 1/4 Cleric creature with “Whenever this creature is dealt damage, put that many +1/+1 counters on it.” Activate only if you're horrific.

Dragon spells you cast cost {1} less to cast.
{1}{R}: Until end of turn, Miyoga Dragonsoul becomes a 2/2 red Dragon creature with flying and “{R}: Miyoga Dragonsoul gets +1/+0 until end of turn.” Activate only as a sorcery.

You may play Molten Basin from your graveyard as long as seven or more cards are in your graveyard.
Molten Basin enters tapped.
{T}: Add {B} or {R}.
Cycling {1}{B}{R} ({1}{B}{R}, Discard this card: Draw a card.)

({T}: Add {B} or {R}.)
Molten Falls enters tapped.
{1}, {T}: Add {B}{B} or {R}{R}.

Whenever you cast a noncreature spell, put a hatch counter on Molten Incubation. Then if it has five hatch counters on it, sacrifice it and choose one —
• Create a 5/5 red Dragon creature token with flying.
• Molten Incubation deals 20 damage to each creature.

Molten Mire enters tapped unless you control a basic land.
{T}: Add {B} or {R}.

Target creature gets +1/+1 until end of turn.
Fabled {2}{R/W}{R/W} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Gain control of target creature with power 2 or less until end of turn. Untap that creature. It gains haste until end of turn.

Target player reveals their hand. You choose a nonland card from it. That player discards that card if it has mana value 2 or less or this spell was foretold.
Foretell {B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Cast this spell only during your turn.
Counter target spell.

Target creature gets +2/+2 until end of turn. You gain 2 life.

Exile target card from a graveyard. If this spell was foretold, create a 2/1 white Soldier creature token.
Draw a card.
Foretell {W} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Look at the top two cards of your library. You may put both of those cards into your graveyard or back on top of your library in any order.
Draw a card.