msem-instigator

When Brawlhost Escapee dies, create a Function token with “Target creature you control fights target creature you don't control.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Haste
Whenever one or more creatures attack, you may discard a card. If you do, draw a card.

When Briarform Apothecary enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
Sacrifice a token: Briarform Apothecary gets +2/+2 until end of turn.

When Briarswine dies, create a 2/2 green Wolf creature token.
Foreshadow {4}{G} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

Prowess
Unveil {2}{U}{R} ({2}{U}{R}: Transform this. Unveil only as a sorcery.)

Lifelink
When Bright-Eyed Adventurer enters, rediscover an enchantment card. (Look at the top card of your library. You may reveal it and put it into your hand if it's an enchantment card. Otherwise, put it back or into your graveyard.)

{T}: Brimstone Grenadiers deals 1 damage to target player.
Whenever you cast an instant or sorcery spell, untap Brimstone Grenadiers.

Whenever Brine Kelpie attacks, you may tap target creature an opponent controls.
Ride {2}{U} ({2}{U}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Whenever Bristled Wolverine attacks, it gets +1/+1 until end of turn.

When Broken Spirit enters, exile target creature an opponent controls until Broken Spirit leaves the battlefield.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Flash
Whenever you cast your second spell each turn, put a +1/+1 counter on Brooding Replacement.

Double strike
Whenever you cast a noncreature spell, you may choose one that hasn't been chosen —
• Tap or untap target permanent.
• Draw two cards, then discard a card.
• Creatures you control get +1/+1 until end of turn.

Flying
You may reveal the second card you draw each turn as you draw it. Whenever you reveal a nonland card this way, copy that card. You may cast the copy. If you don't, Brutal Director deals 2 damage to any target. (You still pay the spell's cost.)

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
When Budding Companion has three or more +1/+1 counters on it, remove them all and transform it.

Whenever you cast a spell for its showcase cost, create a 2/2 blue Drake creature token with flying.

{3}{U}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy.

When Bug Catcher enters, create a 1/1 green Insect creature token.
Whenever a nontoken Insect you control dies, create a 1/1 green Insect creature token.

Whenever you foretell a card or cast a foretold spell, Bugrund's Schemer deals 2 damage to each opponent.

Double strike, vigilance
At the beginning of combat on your turn, create X 1/1 red Dwarf creature tokens with haste, where X is the number of embattled nontoken creatures you control. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

First strike
Ascend {1}{B} ({1}{B}: Exile this creature, then return it to the battlefield transformed. Ascend only as a sorcery.)

Haste
{T}: Discard a card, then draw a card.
Paranoia {2}{R} (You may cast this spell for its paranoia cost when a permanent you control leaves the battlefield.)

Flying
Whenever Buzzing Flitter attacks, you may pay {G}. If you do, untap target permanent.

Other Citizens and Peasants you control get +1/+1.
{2}{G/W}: Look at the top five cards of your library. You may reveal a Citizen or Peasant card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Flying
Whenever you gain life, each opponent loses 1 life.

Defender, reach
Sacrifice Cackling Jack: It deals 3 damage to any target.