msem-instigator

Font of Sorrows and other permanents you control entering the battlefield cause their death knell to trigger.
Death knell — Draw a card. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)

Whenever a creature you control deals combat damage to a player, you may draw a card.
Fleeting {1}{U} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Trample
You may spend black and green mana as though it were mana of any color.
Whenever Closing-Act Abomination attacks, look at the top X cards of your library, where X is the number of colors among cards in your graveyard. Put up to one of them into your hand and the rest on the bottom of your library in a random order.

Enchant player
Whenever enchanted player casts a spell from anywhere other than exile, exile that spell. During that player's next turn, they may cast that card without paying its mana cost.

Flying, vigilance

Flying
When Cerulean Curtain Treasurer enters, audition for blue, then audition for blue again. (Create a 1/1 Construct Actor creature token, a Wizard Role giving 2/2 and prowess, or a Warlock Role giving 2/1 and flying. Roles replace older ones.)

Flash (You may cast this spell any time you could cast an instant.)
When Silk Crane Adept enters, target creature gains hexproof until end of turn.

Gain control of target creature with power X or less.

Target opponent chooses a creature card in your graveyard. Return the chosen card from your graveyard to your hand.

Flying
Ward—Discard a card.
Whenever Kai'Oro enters or attacks, you may exile target nonland card with mana value 3 or less from your graveyard. Until end of turn, you may cast a copy of that card without paying its mana cost.

Create a 1/1 blue Bird creature token with flying, then put the bottom card of your library into your hand.

Put a porcelain counter on each of up to one target creature and up to one target artifact. They become 3/3 colorless artifact creatures and lose all abilities.

Until end of turn, target creature gets +2/+2 and gains trample and “Whenever this creature deals combat damage to a player, investigate.” (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Fahrib Informant can't be blocked by creatures with greater power.
Whenever one or more creatures you control deal damage to an opponent, put a +1/+1 counter on Fahrib Informant.

Conjure Quicksand deals 1 damage to each creature and planeswalker you don't control and each battle you don't protect.

{2}{G}: Rotted Kalak gains indestructible until end of turn.
Revive {3}{B} ({3}{B}, 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.)

Whenever another nonland permanent you control enters, return that permanent to its owner's hand at the beginning of the next end step.

Choose one —
• Exile target artifact.
• Target player exiles two artifacts they control with mana value 0.

When Traversing the Hellwastes enters, create a 1/1 green Scout creature token. It gains haste until end of turn.
Whenever a creature you control enters, you may pay 2 life. If you do, draw a card.

Whenever you cast a legendary spell or play a legendary land, put a +1/+1 counter on Henros, Royal Herald and you gain 1 life.
{2}{W}: Look at the top six cards of your library. You may exile a legendary card from among them. Then shuffle. If the exiled card has mana value less than Henros's power, you may put it onto the battlefield tapped. If you don't, put it into your hand.

Harmony — Target player mills four cards.
When Creeping Pianist enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Lifelink
When Leyran-Pack Outcast attacks, if it's alpha, each player sacrifices a creature.

Enchant creature
Enchanted creature has vigilance.
Whenever enchanted creature attacks or blocks, you gain 2 life.

Prowess
At the beginning of combat on each of your turns, you may draw a card. If you do, discard a card.

(As this Discovery enters and after your draw step, add a progress counter. Stop after you've discovered.)
Target creature or planeswalker you control explores.
You may play an additional land this turn.
C — At the beginning of your upkeep, if you control seven or more differently named permanents, create a 1/1 Scout creature token that's all colors.