msem-instigator

Equipped creature gets +1/+1.
Whenever equipped creature attacks, tap up to one target creature.
Equip {1}

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature gets +1/+0 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy it.)

Choose one —
• Return target creature card from your graveyard to your hand.
• Pay {4}. If you do, return target creature card from your graveyard to the battlefield.

{1}{R}, Discard a card: Draw a card.
{R}: You may put a creature card from your hand onto the battlefield. That creature gains haste. Activate only if twenty or more cards are in your graveyard.

Destroy target creature with power or toughness 2 or less.

Whenever Twilight Dancer attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Each player loses 1 life and mills a card.

Target player loses 1 life. Scry 1.
Fabled {2}{B} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that player.)

When Twilight Vigil enters, scry 2, then put a night counter on it.
Death knell — Put a night counter on Twilight Vigil. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)
Sacrifice Twilight Vigil: For each night counter on it, you gain 1 life and trigger up to one death knell of a permanent you control.

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
Lifelink

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Revive {1}{B} ({1}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Tzelin of the Demon Realm can't block.
Whenever a Demon you control enters, you may pay {B}. If you do, return Tzelin from your graveyard to the battlefield with a +1/+1 counter on it.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Whenever a Demon you control enters, put a +1/+1 counter on Tzelin.
{2}{B}: Sacrifice Tzelin. If you do, each opponent loses life equal to Tzelin's power. If you're in a renaissance, also draw that many cards.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Ulek Windrider envisions an instant or sorcery card, it gets +1/+0 and gains flying until end of turn.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever a creature deals combat damage to a player, if it was encouraged by Unbeholden Navigator this turn, draw a card.

Spend only mana produced by Treasures to cast spells.
{2}, Discard a card: Create two Treasure tokens.

Unceasing Flames deals X damage to any target, where X is 2 plus the number of cards named Unceasing Flames in your graveyard.
Conjure three cards named Unceasing Flames and shuffle them into your main library.

Target creature can't be blocked this turn.
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.”)

Enchant creature
Enchanted creature gets +1/+0 and has menace. (That creature can't be blocked except by two or more creatures.)

{T}, Pay 1 life: Add one mana of any color that a land an opponent controls could produce.

Colossal 2—{4}{B} (You may cast this for its colossal cost to have it enter with two +1/+1 counters; or pay {4}{B} as a sorcery: Put two +1/+1 counters on it if it has none.)
Lifelink

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Enchant land
When Unexplored Regions enters, draw a card.
Enchanted land is an artifact in addition to its other types and has “{T}: Add one mana of any color.”

Return target creature card from your graveyard to your hand.
Inscribe {3}{B} ({3}{B}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Target creature can't block until end of turn. If that creature had a Steed attached to it, unattach that Steed and it can't block until end of turn.
Draw a card.

Conjure six duplicates of target instant or sorcery card in a graveyard into your main library. Then shuffle.
Draw a card.