msem-instigator

You may put a creature or Revelation card from your hand onto the battlefield. Exile that permanent if it would leave the battlefield. If it's a Revelation, it enters the battlefield as a Horror creature.
Coalesce {7}{U}{U} (You may cast this from your graveyard for {7}{U}{U}. If you do, put it onto the battlefield as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

This spell costs {1} less to cast for each storied permanent you control. (Enchantments and legendary permanents are storied.)
Counter target spell.
Draw a card.

Creatures you don't control get -1/-1.
Mirage {1}{B} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Vigilance, trample
Whenever another Horror enters the battlefield under your control, choose one —
• Destroy target artifact or enchantment.
• You gain 4 life.
• Apex Abomination fights another target creature.

At the beginning of your upkeep, if an opponent controls more creatures than you, you may reveal the top seven cards of your library. Target opponent chooses a creature card revealed this way. Put that card onto the battlefield, and the rest into your graveyard.

Create an 8/8 blue Kraken creature token with hexproof.
Rerun (If you cast this from your hand, exile it as it resolves. Whenever a creature you control dies, you may cast this card from exile without paying its mana cost.)

At the beginning of your upkeep, if you control ten or more storied permanents, you win the game. (Enchantments and legendary permanents are storied.)

When Apprentice Summoner enters the battlefield, search your library for a creature card with mana value 1 or less, put it onto the battlefield, then shuffle.

Enchant artifact or creature
At the beginning of each upkeep, if enchanted permanent is tapped, untap it.
You control enchanted permanent.

Counter target spell. Draw a card, then discard a card.

Flying, lifelink
Improve {1}{W/B} ({1}{W/B}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Once each turn, when you gain life, you may have each opponent lose 2 life.

Flying
When Arbiter of Silence enters the battlefield, exile all other creatures until Arbiter of Silence leaves the battlefield. (They return to the battlefield under their owners' control.)

Flash
Flying
As long as an opponent controls more creatures than you, Arbiter of the Scales gets +2/+2 and has first strike and lifelink.

This spell costs {1} less to cast for each differently named land you control.
Reach, trample

Counter target spell. If a permanent spell is countered this way, create a Gold token. (It's an artifact with “Sacrifice this artifact: Add one mana of any color.”)

Prowess
When Arcane Dredger enters, return target instant or sorcery card from your graveyard to your hand.

Whenever Arcane Metalcrafter or another Wizard you control attacks, create a 1/1 colorless Construct artifact creature token that's tapped and attacking.
Whenever a Construct you control dies, Arcane Metalcrafter deals 1 damage to each opponent.

Counter target spell. If that spell is countered this way, until the end of your next turn the next spell you cast that shares a type with it costs {X} less to cast, where X is the countered spell's mana value.

When Arcanomancer enters the battlefield, return up to one target instant card and up to one target sorcery card from your graveyard to your hand.

Flying
When Arcanum Owl enters the battlefield, you may return target instant or sorcery card from your graveyard to your hand.

When Archaeomancer enters the battlefield, return target instant or sorcery card from your graveyard to your hand.

This spell costs {1} less to cast for each enchantment you control.
Flying, lifelink, trample
Disturb {6}{B}{B}. That spell costs {1} less to cast for each enchantment you control. (You may cast this card from your graveyard transformed for its disturb cost.)

Flying
Concord — When Archangel of Accord enters the battlefield, if there are four or more card types among permanents you control, destroy all other creatures.

Flying
You may cast enchantment spells from your graveyard.
Whenever an enchantment enters the battlefield under your control, draw a card.

Flying, lifelink
{2}{W}{W}, Exile Archon of Sunrise from your graveyard: Create a token that's a copy of it, except it's an Aura enchantment with enchant creature and “Enchanted creature gets +4/+4 and has flying and lifelink.” Activate only as a sorcery.