msem-instigator

Whenever one or more creatures you control deals combat damage to a player, you may sacrifice one of them. When you do, destroy target creature defending player controls, then you and the destroyed creature's controller draw a card.

Haste
Whenever Arpechian Tiger attacks, you may sacrifice a land. If you do, Arpechian Tiger deals 3 damage to target creature or planeswalker.

Trample
When Arpechian Yatte enters, put a +1/+1 counter on each other creature you control.
Whenever another creature you control enters, put a +1/+1 counter on Arpechian Yatte.

{1}{G/W}: Put a +1/+1 counter on Artful Chari.
Whenever you cast an instant or sorcery spell, you may remove a number of +1/+1 counters from Chari equal to that spell's mana value. If you do, copy that spell, and you may choose new targets for the copy.

When Artificial Wayfinder enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

When Artillery Mage enters, it deals 5 damage to target creature you don't control.
{5}{R}, {T}, Discard a card: Artillery Mage deals 5 damage to target creature you don't control.

Flash
When Artisan of Marrow enters, exile another target creature until Artisan of Marrow leaves the battlefield.

Flying
Clerics you control are Angels in addition to their other types.
Attacking Angels you control get +1/+0.

Flying
Clerics you control are Demons in addition to their other types.
Attacking Demons you control have deathtouch.

Flash
When Ascetic of Imbalance enters, draw two cards, then discard two cards. If you discarded two cards that don't share a type, Ascetic of Imbalance deals 2 damage to any target.

Flying
When Ascetic of the Folded Fan enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Each creature you control with a +1/+1 counter on it has vigilance.

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Ash Breather deals combat damage to a player, you may discard a card. If you do, draw a card.

First mate — Twelve or more cards in your starting deck are Dragons or have “Dragon” in their printed rules text. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Dragon spells you cast cost {1} less to cast.
Whenever Ashe attacks, it deals X damage to any target, where X is the number of Dragons you control.

When Asking Imp enters, an opponent may pay 2 life. If they do, return Asking Imp to its owner's hand.

Menace (This creature can't be blocked except by two or more creatures.)
Whenever a creature you control deals combat damage to a player, you may have Aspect of Rage deal 1 damage to any target.

When Asphodel Gravedealer dies, choose one —
• Put a +1/+1 counter on target creature you control.
• Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Whenever a storied permanent you control enters, tap target creature an opponent controls. (Enchantments and legendary permanents are storied.)

Rhapsody {3}{W}{W} (Pay {3}{W}{W} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Lifelink

First strike
Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Put a +1/+1 counter on each of up to two other target creatures you control.
[Lore III] Remove all lore counters from Astral Capricine. Create two 0/1 white Goat creature tokens.

Menace
Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Exile the top card of your library. You may play that card this turn.
[Lore III] Remove all lore counters from
Astral Cerberus. It deals 3 damage to up to one target creature.

Deathtouch
Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] You may sacrifice another creature. If you do, draw a card.
[Lore III] Remove all lore counters from Astral Leech. Each opponent sacrifices a creature.

When Astute Sceneweaver enters, proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Flying
Whenever Atieh's Disciple attacks, scry 1.

Flying, vigilance, lifelink
Whenever Atieh's Favored attacks, put a +1/+1 counter on each other Angel and/or Nephilim creature you control.

Rhapsody {4}{R}{R} (Pay {4}{R}{R} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Trample
Whenever Attuned Slayer deals combat damage to a player, exile that many cards from the top of your library. You may play those cards this turn.