msem-instigator

Target player mills X cards, where X is the number of cards in your graveyard.
Flashback {3}{U/B}{U/B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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

Lifelink
{2}, Remove two counters from Acrimony: Each opponent loses 2 life and you gain 2 life.
At the beginning of your end step, for each permanent, move a counter from that permanent onto Acrimony.

Flash
Flying, first strike, lifelink

Creatures your opponents control get -1/-0.

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.
Draw a card.

Exile a nonland card from target opponent's graveyard. Copy it. You may cast the copy without paying its mana cost. (Copies of permanents enter as tokens.)

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Whenever a -1/-1 counter is put on a creature, you may create a 1/1 green Elf Druid creature token.

Search your library for a creature card with mana value 3 or less, put it onto the battlefield, then shuffle. It gains haste until end of turn. Return it to your hand at the beginning of the end step.

Flying
Whenever another creature you control enters, Adavene, Dean of the Arts deals 1 damage to each opponent.
Whenever a creature you control deals combat damage to a player, you may exile it, then return it to the battlefield.

When Adept Electromancer enters, scry 2, then reveal the top card of your library. If it's an instant or sorcery card, put it into your hand.

Prowess
When Adept of Signals enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
Tokens you control have “{2}, {T}: Sacrifice this token: Draw a card.”

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.

Converge — Admin of Asthenia enters with a +1/+1 counter on it for each color of mana spent to cast it.
Admin of Asthenia can't attack unless its power is 4 or greater.

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

Flying
As long as there are five or more different creature types among creatures you control, Adventuring Guildmage gets +1/+0 and has hexproof.

Lifelink
Whenever an opponent loses life, you may pay {2}. If you do, choose one—
• That player discards a card.
• Put a +1/+1 counter on Adversary Ancestor.

When Aether Road Caravan enters, gain control of target nonland permanent with mana value 3 or less for as long as you control Aether Road Caravan.

When Aether Sculptor enters, create a tapped colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Create a token that's a copy of target artifact or enchantment you control.

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

When Aftermath of the Surge enters, create two Treasure tokens.
{1}{U}, Sacrifice two artifacts: Draw two cards.
{3}{U}, Sacrifice four artifacts: Create an 8/8 blue Kraken creature token. It can't block this turn.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Scry 2.
II — Draw two cards.
III — Spells you cast this turn cost {2} less to cast.

Deception {2}{B} ({2}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Agent of Long Shadows deals combat damage to a player, you may put a Rogue card from your hand or graveyard onto the battlefield.