msem-instigator

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.)

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.”)

Enchant creature
Enchanted creature gets +2/+2 and has lifelink.

All creatures get -4/-4 until end of turn.

Whenever a creature card is put into your graveyard from the battlefield, exile it. You lose life equal to that card's mana value. Put it onto the battlefield tapped at the beginning of your next upkeep.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Return target creature card from your graveyard to the battlefield. If it was put there from the battlefield this turn, create a token that's a copy of it. If you're in a renaissance, create a token that's a copy of it.

Flying
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.)
When Bitter Corvus enters, you may reveal the top X cards of your library, where X is Bitter Corvus' power. You may put up to one card revealed this way into your hand. You lose life equal to its mana value. Put the rest into your graveyard.

Target player discards a card. Return a creature card from your graveyard to your hand.

Target opponent reveals their hand. You choose an instant or sorcery card from it or a card from their graveyard. Exile that card.

Whenever you put one or more -1/-1 counters on a creature, create that many 1/1 black Faerie creature tokens with flying.

Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Bitter Wanderer desecrates a permanent, each opponent loses 2 life and you gain 2 life.