msem-instigator

When Aethermancer's Companion enters, aetherize up to two other non-Cat permanents you control. (Create tokens that are copies of each of them, then exile them.)
Recite {5}{W}{U} (You may cast this spell from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)

Flying, hexproof
At the beginning of your end step, put an exiled card with an ancestry counter on it on the bottom of its owner's library, then scry 2. If there is exactly one card exiled with an ancestry counter on it, transform Atieh.

Flying, vigilance
When you unveil Graced Theurge, draw a card.

Pressure {3}{U}{B} (You may cast this spell for its pressure cost if there are seven or more cards in your graveyard.)
Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
{U}{B}, Reveal Cuxuri Beckoner from your hand: Target player mills two cards.

Hexproof
Discard two cards: You may cast target instant or sorcery card in your graveyard this turn. If that spell would be put into a graveyard, exile it instead.
At the beginning of your end step, if you have two or fewer cards in hand, transform Fahrib.

Flash
When Kaivilu, Ocean Warden enters, creatures your opponents control get -2/-2 and lose all abilities until end of turn.

Whenever you cast an instant or sorcery spell, Kederekt Deepdweller gains your choice of indestructible, lifelink, or menace until end of turn.
Whenever Kederekt Deepdweller deals combat damage to a player, you draw a card and that player discards a card.

Menace
Whenever Masoh enters or attacks, each opponent that has more than four cards in hand discards cards equal to the difference. Then if you have fewer than four cards in hand, draw cards equal to the difference.

Flying
Whenever you foretell a card or cast a foretold spell, each opponent loses 3 life unless they sacrifice a creature or discard a card.

Flying
Whenever Prismatic Scyphozoa attacks or blocks, target player mills three cards.
When Prismatic Scyphozoa dies, create four 1/1 blue Elemental creature tokens with flying.

Return target creature you control and target creature you don't control to their owners' hands. Target player discards a card.
Coalesce {4}{U}{B} (You may cast this from your graveyard for {4}{U}{B}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Terrors of Cuxuri Trench can't block.

Menace
Whenever one or more cards leave your graveyard or Watchers of the Veil leaves your graveyard, you may draw a card. If you do, discard a card.

When Wretched Spawn enters, you may return target permanent to its owner's hand. If you do, that player discards a card.
Unearth {4}{U}{B} ({4}{U}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the end step or if it would leave the battlefield. Unearth only as a sorcery.)

Abyss Howler must be blocked if able.
Whenever Abyss Howler becomes blocked, defending player loses 2 life and you gain 2 life.

Flying
{1}, Sacrifice a creature: Put a +1/+1 counter on Bloodthirsty Manticore. It gains indestructible until end of turn. Tap it.
Surpass {4}{B}{R} ({4}{B}{R}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

{1}, Sacrifice a creature: Create a Treasure token. Exile the top card of your library. You may play that card this turn.

Flying
When Kaalia's Abomination enters or dies, it deals 2 damage to target opponent. Then that player discards two cards.

Bleed {1}{B}{R} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
At the beginning of each end step, if an opponent lost life this turn, draw two cards, then discard a card at random.

Glorious end — When Toros the Warchief dies, if it was tapped, return it to the battlefield at the beginning of the next end step.
Attacking creatures you control have deathtouch.

Flying, haste
Whenever another creature dies, Twinfire Dragon gets +1/+0 until end of turn.

{T}: Return target creature card 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. That creature salvages a card. (Exile one from your graveyard until that creature leaves the battlefield. Whenever that creature deals combat damage to a player, put a card it salvaged into your hand.)

Trample
When Wasteland Ravagers enters, you may sacrifice a land or exile a land card from your graveyard. If you do, creatures you control get +1/+0 and gain haste until end of turn.

Trample
Auspicious Qilin must be blocked if able.

Whenever a land you control enters, add one mana of any color.
Whenever Enraged Fangwurm attacks, you may sacrifice a land. If you do, Enraged Fangwurm deals 2 damage to target player or planeswalker.

Whenever Glorybound Chorister attacks, put a +1/+1 counter on each other attacking creature you control.