msem-instigator

Whenever a non-Spirit creature deals combat damage to a player, destroy that creature. Its controller creates a 1/1 colorless Spirit creature token.

Once each turn, when Atal, the Shroudmaker enters or you attack with one or more Horrors, you may create two tapped 1/1 colorless Human creature tokens. If Atal isn't a token, creatures you control gain flying until end of turn.
{2}{W}{W}, Discard Atal: Create a token that's a copy of Atal, the Shroudmaker, except it's 4/4 and isn't legendary. Activate only as a sorcery.

Whenever a nonbasic land becomes tapped or enters tapped, it doesn't untap during its controller's untap steps for as long as Ataraxia remains on the battlefield.

Whenever a land you control enters, you may pay {2}{G}. If you do, put a +1/+1 counter on Atdrik Ravager.

Vanishing 4 (This permanent enters with four time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Equipped creature gets +3/+3.
Equip {2}

Put a +1/+1 counter on target attacking creature.
Draw a card.

Indestructible
As long as your devotion to white and black is less than seven, Athreos isn't a creature.
Other creatures you control have lifelink.
Each player and cards in graveyards can't be the targets of spells or abilities your opponents control.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

{2}: Atieh's Acolyte gains your choice of flying, vigilance, or lifelink until end of turn.
Whenever another Angel or Nephilim you control enters, put a +1/+1 counter on Atieh's Acolyte.
Surpass {4}{W}{U} ({4}{W}{U}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Choose two —
• Put two +1/+1 counters on target creature.
• Atieh's Command deals damage to any target equal to the greatest power among creatures you control.
• You gain life equal to the greatest power among creatures you control.
• Draw cards equal to the greatest power among creatures you control, then discard three cards.

Whenever Atieh's Destiny or another creature you control enters, you gain 1 life and scry 1.

Flying
Whenever Atieh's Disciple attacks, scry 1.

Flying
When Atieh's Elite enters, judge another target creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)
Whenever you honor a creature, until end of turn, that creature has base power and toughness 4/4, gains flying, and becomes an Angel in addition to its other types.

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Flash
When Atieh enters, return target noncreature spell to its owner's hand.
{W}{U}: Angel — You gain 2 life and draw a card.
{2}{W}{U}: Elder — Atieh gains “Each opponent can't cast more than one spell each turn.”

When Atlas of Worlds enters, search your library for any number of land cards with different names and exile them, then shuffle.
You may play lands exiled with Atlas of Worlds.

Prevent all combat damage that would be dealt this turn.
Create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Choose one or both —
• Prevent all combat damage that would be dealt to creatures this turn.
• Detain target creature. (Until your next turn, that creature can't attack or block and its activated abilities can't be activated.)

When Atrocity of Flesh enters, destroy target nonland permanent.
When Atrocity of Flesh dies, you may exile it. If you do, return target card from your graveyard to your hand.

Destroy target creature.

When you discard Attack Vector, you may cast it from your graveyard.
Exile the top two cards of your library. Until the end of your next turn, you may play one of those cards.

Vigilance
{T}: Add one mana of any color.
Satrapycycling {2} ({2}, Discard this card: Search your library for a Satrapy card, reveal it, put it into your hand, then shuffle.)

First strike (This creature deals combat damage before creatures without first strike.)
When Attended Knight enters, create a 1/1 white Soldier creature token.

Attentive Glider gets +2/+2 and has flying as long as you cast an Adventure spell or a permanent you controlled explored this turn.

Enchant creature
As long as you control an untapped creature, enchanted creature can't attack or block.

(Add a quest counter as this enters. Sacrifice after 3.)
1, 2 — At the beginning of your end step, if you cast no spells this turn, add a quest counter.
3 — Untap each creature you control. Until your next turn, they gain “{T}: Scry 1.”
Scry 2, then draw two cards. You gain 2 life.