msem-instigator

When Bayou Courier enters, you may pay 2 life. If you do, create a 3/2 green Crocodile creature token with trample.

Bearer of Fables gets +1/+1 for each enchantment you control.
{2}{G}: Look at the top four cards of your library. You may reveal an enchantment card or a card with fabled from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Inspired — Whenever Bearer of Vile Incense becomes untapped, create a 0/1 black Cultist creature token with “{1}{B}{B}, Sacrifice three Cultists: Create a 5/5 black Demon creature token.”

Whenever you cast an instant or sorcery spell, each opponent loses 1 life and Beast of Pestilence gets +1/+1 until end of turn.

Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, put a quest counter on Beckon Darkness.
At the beginning of your upkeep, if Beckon Darkness has four or more quest counters on it, return target creature card from your graveyard to the battlefield.

Bloodprice {2}{B}{B} (You may cast this card by sacrificing a creature and paying its bloodprice.)
Return target creature card from your graveyard to your hand. If you cast this spell for its bloodprice, return that card to the battlefield instead.

Whenever you cast an enchantment spell, you draw a card and you lose 1 life.
Whenever one or more counters are put on an enchantment you control, you gain 1 life and each opponent loses 1 life.

Bedfellow can't block or be blocked.
Exile two cards from your graveyard: Bedfellow gets +1/+1 until end of turn.

All creatures that aren't embattled get -5/-5 until end of turn. If a creature would die this turn, exile it instead. (A creature is embattled if it has a counter on it or a permanent its owner controls attached to it.)

When Beguiling Witch enters, nourish 1. (To nourish 1, either put a +1/+1 counter on this creature or create a 1/1 white Citizen creature token.)
Whenever another creature dies, each opponent mills X cards, where X is Beguiling Witch's power.

Destroy target creature.
Civilized — You gain 3 life if you control an artifact, a creature, and an enchantment.

When Bellani Mystic enters, target player mills two cards.

Whenever another creature you control dies, put a +1/+1 counter on Belligerent Mob.

(Transform this if it's not attached to a creature. Pay {2}{B}{B} as a sorcery to unattach it.)
Enchant creature you control
Belmord Blood-Coach's rider gets +3/+3 and has deathtouch.
Whenever Belmord Blood-Coach's rider attacks, you may return target creature card with mana value less than its rider's power from your graveyard to the battlefield tapped.

Other Knights and Soldiers you control get +1/+0.
Cowards can't block Knights and Soldiers you control.
When Belmord Bloodcurdler enters, target creature an opponent controls becomes a Coward in addition to its other types. (This effect last indefinitely.)

Siphon (Each -1/-1 counter you put on your creatures up to their remaining toughness while casting this pays for {1}.)
Destroy target creature or planeswalker.

Flying
Belmord can't block.
{1}{B}: Create a 1/1 black Bat creature token with flying and “This creature can't block.” Activate only if a player gained or lost life this turn and only once each turn.

Mill four cards, then you may return a creature or planeswalker card from your graveyard to your hand.
As long as Beneath the Zhedina is in your graveyard, other cards in your graveyard can't be the target of spells or abilities your opponents control.

Flying
Sacrifice six Swamps: Return Berbarus Unsealed from your graveyard to the battlefield with an indestructible counter on it. You draw six cards and you lose 6 life.

Target opponent reveals their hand. You choose a nonland permanent card from it. That player discards that card.

{T}, Exert Bestower of Princely Sin: You may sacrifice another creature. If you do, target opponent may sacrifice a permanent that shares a card type with it. If they don't, that player loses 1 life and you draw a card. Repeat this process for artifact, enchantment, land, and planeswalker. Activate only as a sorcery.

Return up to two target creature cards with mana value X or less from your graveyard to the battlefield. They can't block this turn.

Return all creature and planeswalker cards from your graveyard to the battlefield.

When Bezoarbeast dies, each opponent loses 2 life and you create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)