msem-instigator

Once each turn, when Vedu, the Deepdrinker enters or you attack with one or more Horrors, you may tap up to two target permanents. If Vedu isn't a token, put two stun counters on each of those permanents.
{2}{U}{U}, Discard Vedu: Create a token that's a copy of Vedu, the Deepdrinker, except it's 4/4 and isn't legendary. Activate only as a sorcery.

Deathtouch
When Vision Beyond the Waters enters, each player sacrifices two creatures other than this creature.

Put two +1/+1 counters on up to one target creature.
Coalesce {6}{G}{G} (You may cast this from your graveyard for {6}{G}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Flying, trample
When Whisper in the Rift enters, target player mills half their library, rounded down.
When Whisper in the Rift dies, you may cast up to two instant, sorcery, and/or creature cards from among opponent's graveyards without paying their mana cost.

Destroy all non-Horror creatures.
Coalesce {8}{W}{W} (You may cast this from your graveyard for {8}{W}{W}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

When Wurgelurg dies, each opponent discards three cards, sacrifices three creatures, and loses 3 life. You draw three cards, create three tapped 2/2 black Zombie creature tokens, and gain 3 life.
Foreshadow {7}{B}{B} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

This spell costs {1} less to cast for each creature that died this turn.
At the beginning of your upkeep, put target creature card from a graveyard onto the battlefield under your control.
{1}, Sacrifice another creature: Zarad, the Final Adversary gains indestructible until end of turn.

When 11-A Lionheart enters, it deals 2 damage to each nonartifact creature.

Each player mills four cards.
Coalesce {5}{U}{U} (You may cast this from your graveyard for {5}{U}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
When A Vision Too Vast enters, you may cast target noncreature, nonland card with mana value 4 or less from a graveyard without paying its mana cost.

Vigilance, reach
As a noncreature spell resolves, exile it instead of putting it anywhere else.

At the beginning of your end step, you lose 3 life unless you sacrifice a creature.

Trample
Each creature you control with a counter on it has trample.

Reach, vigilance
When Amorphous Tyrant enters, another target creature you control deals damage equal to its power to target creature or planeswalker you don't control.
Evoke {G} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

If another multicolored card would be put into your graveyard from anywhere other than your hand or library, if no cards exiled with An'yama, Elder Guardian are exactly that card's colors, you may instead exile that card and put a +1/+1 counter on An'yama.
As long as An'yama has four or more counters on them, they have protection from everything.

Ward {3}

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Whenever Andazir enters or transcends, each opponent sacrifices a nonland permanent.
{1}{B}{R}: Demon — Create four 1/1 black Snake creature tokens with deathtouch.
{2}{B}{R}: Elder — You draw three cards and you lose 3 life.

Protection from instants and from sorceries
At the beginning of your upkeep, sacrifice another creature. If you do, put a +1/+1 counter on Andazir, the Crownless.
At the beginning of your end step, if you control four or fewer creatures, transform Andazir.

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

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

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

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, lifelink
When Archdemon Shilgengar enters, exile all land cards from your graveyard, exchange your graveyard and library, then shuffle your library.
You can only cast spells by paying life equal to their mana value rather than paying their mana cost.

When Arpechian Stag enters, create a 3/3 red Elk creature token with haste, a 3/3 green Elk creature token with trample, and a 3/3 white Elk creature token with vigilance.

Haste
Augmented — When Attuned Lifeform enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on each creature you control. They gain vigilance until end of turn.

When Awoken Animus enters, create two 1/1 colorless Shapeshifter creature tokens with changeling. (They're every creature type.)
{2}, Discard Awoken Animus: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.