msem-instigator

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.)

Hexproof
Whenever attackers are declared, the active player may pay {2} for each creature attacking you. Then you may have Bridge Kalak become an X/X Troll creature until end of turn, where X is the number of times that player didn't pay mana this way.

This spell costs {2} less to cast if you control a transformed permanent.
Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

When Bridled Narwhal enters, you gain 5 life.

Deathtouch
When Brig of the Damned enters, return target creature card from your graveyard to your hand. If that card's mana value is 2, you may return it to the battlefield instead.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

Shuffle your hand and graveyard into your library, then draw seven cards. You may have your life total become 10. You may cast a spell from your hand without paying its mana cost. Exile Bright Future.

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.)

Flash
When Brightsouled Guardian enters, return up to one target nonland permanent to its owner's hand.

Flying
Whenever you cast a spell from anywhere other than your hand, Brightwing Sphinx gains vigilance until end of turn.

Augmented — Whenever Bril, the Oltenen Emissary enters or attacks, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, destroy target permanent.

Tap up to four target nonland permanents. Nonland permanents your opponents control don't untap during their controller's next untap step.

Flying
When Brilliant Griffin enters, target creature gets +2/+2 until end of turn.

Brilliant Runepearl enters tapped.
Whenever you cast a permanent spell, you gain 1 life.
{T}: Add one mana of any color. Spend this mana only to cast permanent spells.

{2}{R}, Sacrifice a creature: Target creature can't block this turn.

{2}{R}: Target creature can't block Brimstone Courser this turn.
Ride {3}{R}{R} ({3}{R}{R}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

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

Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, Brine Cultist can't be blocked this turn.
{5}{U}: Draw a card.

Defender
When Brine Duelist enters, create a Treasure token. (It's an artifact with “{T}, Sacrifice this permanent: Add one mana of any color.”)
{W}{U}{B}{R}{G}: Put a +1/+1 counter on Brine Duelist. It loses defender.

Whenever you draw a card, you may have target player mill two cards.

Destroy target creature with flying.
Draw a card.

Trample
When Bringer of Armies enters, recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

Flying, vigilance
Protection from Humans (This creature can't be blocked, targeted or dealt damage by Humans.)

At the beginning of your upkeep, you may discard a land card. When you do, create a 2/2 green Wolf creature token.

Target player draws seven cards, then their life total becomes equal to the number of cards in their hand.