msem-instigator

When Abomination Broodmother dies, create a 3/2 green Horror creature token.

When Abomination Emissary enters, target player mills six cards.

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

This spell costs {2} less to cast if you've cast both an instant spell and a sorcery spell this turn.
Haste

Revive {3}{G} ({3}{G}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

When Adamant Healer enters, you may move any number of counters from target creature onto another target creature with the same controller.

Lifelink
Converge — When Adapted Explorer enters, it deals X damage to up to one target tapped creature, where X is the number of colors of mana spent to cast it.

Flash
When Adiran Distractor enters, return up to one target creature you control and up to one target creature you don't control to their owners' hands.

As an additional cost to cast this spell, exile two permanent cards from your graveyard.
You may cast Adiran Survivors from your graveyard.

Whenever you cast a Pirate spell, create a 1/1 blue and red Pirate creature token with haste.

Civilized — Adorned Naga gets +2/+0 and has menace as long as you control an artifact, a creature, and an enchantment.

Flying, haste
Whenever Adoroth, the Baneful attacks, forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)
{1}{R}{R}: Adoroth, the Baneful deals 4 damage to any target. Activate only if you have no cards in hand.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Aether Recoverer envisions a creature card, return target noncreature card from your graveyard to your hand.

Defender, reach
Aetherlock Effigy can block an additional creature each combat.
When Aetherlock Effigy dies, create two 1/1 black Bird creature tokens with flying.

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
When Ageless Lorekeeper enters, you may discard your hand. When you do, draw three cards.

This spell can't be countered.
Flying
Whenever Ajax, Tyrant of the Empire enters or deals combat damage to a player, draw a card.
Whenever Ajax or another Dragon you control attacks, that Dragon deals 2 damage to any target.

Skip your draw step.
If a card would be put into your graveyard, exile it instead.
At the beginning of your upkeep, return a card from your graveyard to your hand. If you can't, you draw a card and you lose 1 life.

When Alaina enters, each opponent loses X life and you gain X life, where X is the number of Clerics you control.
{W}{B}, Pay 2 life: Return Alaina from your graveyard to your hand. Activate only if you have more life than your starting life total.

At the beginning of each upkeep, if no spells were cast last turn, create a 2/2 green Wolf creature token.
{3}{R/G}{R/G}: Albin, the Huntmaster and creature tokens you control get +2/+2 and gain trample until end of turn.

Menace
Whenever a creature blocks, put a -1/-1 counter on that creature at end of combat.
Creatures with -1/-1 counters on them can't block.

Trample
Whenever a creature attacks, Alpha Stag gets +2/+2 until end of turn.

Flying, prowess
Whenever an artifact you control enters, you may draw a card. If you do, discard a card.

At the beginning of each other player's upkeep, draw a card, then discard a card unless you have Am'atambi, Fable Weaver deal 3 damage to you.
You may reveal creature cards as you draw them. Once each turn, when you reveal a creature card this way, you may pay {3}. If you do, create a token that's a copy of it, except it's 3/3.

Flying
Soldiers and Knights you control get +1/+1.