msem-instigator

{2}{W}: Audacious Knight gains first strike and vigilance until end of turn. (It deals combat damage before creatures without first strike. Attacking does not cause it to tap.)

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

When Auramancer enters, you may return target enchantment card from your graveyard to your hand.

When Automated Blademaster enters, create a colorless Equipment artifact token named Sword with “Equipped creature gets +1/+1” and equip {1} and attach it to Automated Blademaster.

{2}: Avaricious Ghul gets +1/+1 until end of turn. If mana from a Treasure was spent to activate this ability, put a +1/+1 counter on Avaricious Ghul instead.

Deathtouch
Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When Avatar of Amosis enters, if tribute wasn't paid, you may destroy target creature.

Crocodile creatures you control get +1/+1.
Avatar of Senmut and Crocodile creatures you control can't be blocked as long as you control four or more Islands.

Flying
Harmony — Until the end of your next turn, you may cast target instant or sorcery card from your graveyard. If that card would be put into your graveyard, exile it instead.
When Aven Acoustimancer enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Kicker {U} (You may pay an additional {U} as you cast this spell.)
Flying
If Aven Ranger was kicked, it enters with a +1/+1 counter on it.

Flying
When Aven Strategist enters, return up to one target creature to its owner's hand.

Flying, vigilance

When Azure Archaeologist enters, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
{2}, {T}, Sacrifice a Clue: Draw two cards, then discard a card.

Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Back-Alley Vandal desecrates a permanent, put a +1/+1 counter on Back-Alley Vandal.

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)

Lifelink
At the beginning of your end step, if you gained life this turn, put a +1/+1 counter on Backstage Manager.

When Backstage Tinkers enters, you may return an artifact card from your graveyard to your hand.

Menace, haste

Prowess
Whenever Balefire Conjurer attacks, you may pay {1}{R}. If you do, exile the top card of your library. You may play that card until the end of your next turn.

Menace
As long as Balefire Harbinger is attacking, creatures in its pack can't be blocked unless defending player pays {1} and 1 life for each creature they control that's blocking one of those creatures. (Two or more creatures you control with equal power are in a pack.)

This spell costs {U} less to cast if you dealt combat damage to a player this turn with a Rogue.
Flying
When Balloon Voyager enters, draw a card.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Bane of Sanity enters, if it engorged a creature card, target player discards two cards.

Haste
Whenever Banished Companion attacks, it deals 2 damage to you.

When Banished Prophet enters, you may remove a counter from a permanent you control. If you do, put a +1/+1 counter on another target creature you control.

Trample
Whenever another Dwarf you control enters, create a colorless artifact token named Ale. It has “{T}, Sacrifice this artifact: Target creature gets +2/+0 until end of turn. Activate only as a sorcery.”

Vigilance
{1}{W}: Barbarian Axe Flinger gains double strike until end of turn.