Aether Flash

Whenever a creature enters, Aether Flash deals 2 damage to it.

Blood Vassal

Bloodstone Cameo

Bog Witch

Belbe's Portal

As Belbe's Portal enters, choose a creature type.
{3}, {T}: You may put a creature card of the chosen type from your hand onto the battlefield.

Blood Pet

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your first main phase, add {B} for each charge counter on Black Market.

Black Mana Battery

{2}, {T}: Put a charge counter on Black Mana Battery.
{T}, Remove any number of charge counters from Black Mana Battery: Add {B}, then add an additional {B} for each charge counter removed this way.

Bladewing the Risen

Flying
When Bladewing the Risen enters, you may return target Dragon permanent card from your graveyard to the battlefield.
{B}{R}: Dragon creatures get +1/+1 until end of turn.

Ashnod's Altar

Bladewing's Thrall

Bladewing's Thrall has flying as long as you control a Dragon.
When a Dragon enters, you may return Bladewing's Thrall from your graveyard to the battlefield.