Bloodthrone Vampire

Sacrifice a creature: Bloodthrone Vampire gets +2/+2 until end of turn.

Blood Servitor

When Blood Servitor enters, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")

Bloodhunter Bat

Flying
When Bloodhunter Bat enters, target player loses 2 life and you gain 2 life.

Blood Fountain

When Blood Fountain enters, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")
{3}{B}, {T}, Sacrifice Blood Fountain: Return up to two target creature cards from your graveyard to your hand.

Blood Burglar

During your turn, Blood Burglar has lifelink.(Damage dealt by this creature also causes you to gain that much life.)

Bog Serpent

Bog Serpent can't attack unless defending player controls a Swamp.
When you control no Swamps, sacrifice Bog Serpent.

Accursed Marauder

When Accursed Marauder enters, each player sacrifices a nontoken creature of their choice.

Dimir House Guard

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Sacrifice a creature: Regenerate Dimir House Guard.
Transmute {1}{B}{B} ({1}{B}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Blood Pact

Target player draws two cards and loses 2 life.

Wither and Bloom

Target creature gets -3/-3 until end of turn.
{1}{B}, Exile Wither and Bloom from your graveyard: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Swamp

Bog Raiders

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Night's Whisper

Retrofitted Transmogrant

{3}{B}: Return Retrofitted Transmogrant from your graveyard to the battlefield tapped with two +1/+1 counters on it.

Blood-Toll Harpy

Flying
When Blood-Toll Harpy enters, each player loses 1 life.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Bog Imp

Flying (This creature can't be blocked except by creatures with flying or reach.)

Bog Down

Kicker—Sacrifice two lands. (You may sacrifice two lands in addition to any other costs as you cast this spell.)
Target player discards two cards. If this spell was kicked, that player discards three cards instead.

Bog Glider

Flying
{T}, Sacrifice a land: Search your library for a Mercenary permanent card with mana value 2 or less, put it onto the battlefield, then shuffle.

Blood Pet

Boggart Loggers

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
{2}{B}, Sacrifice Boggart Loggers: Destroy target Treefolk or Forest.

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Dark Ritual

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Bloodcrazed Socialite

Menace
When Bloodcrazed Socialite enters, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")
Whenever Bloodcrazed Socialite attacks, you may sacrifice a Blood token. If you do, it gets +2/+2 until end of turn.

Refurbished Familiar

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When Refurbished Familiar enters, each opponent discards a card. For each opponent who can't, you draw a card.

Bloodcrazed Hoplite

Heroic — Whenever you cast a spell that targets Bloodcrazed Hoplite, put a +1/+1 counter on it.
Whenever a +1/+1 counter is put on Bloodcrazed Hoplite, remove a +1/+1 counter from target creature an opponent controls.

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Bog Initiate

Blood Tithe

Each opponent loses 3 life. You gain life equal to the life lost this way.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Bloodrage Vampire

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Blood Curdle

Destroy target creature. Put a menace counter on a creature you control. (It can't be blocked except by two or more creatures.)

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik, Son of Yawgmoth.

Blood Celebrant

{B}, Pay 1 life: Add one mana of any color.

Sign in Blood

Bog Rats

Bitter Triumph

As an additional cost to cast this spell, discard a card or pay 3 life.
Destroy target creature or planeswalker.

Blood Glutton

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Bloodrite Invoker

{8}: Target player loses 3 life and you gain 3 life.

Bog Smugglers

Boggart Birth Rite

Return target Goblin card from your graveyard to your hand.

Dreamdrinker Vampire

Lifelink
{1}{B}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Dreamdrinker Vampire, it gains menace until end of turn.

Blood Seeker

Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Bloodflow Connoisseur

Sacrifice a creature: Put a +1/+1 counter on Bloodflow Connoisseur.

Assassinate

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Witch's Cottage

({T}: Add {B}.)
Witch's Cottage enters tapped unless you control three or more other Swamps.
When Witch's Cottage enters untapped, you may put target creature card from your graveyard on top of your library.

Blood Vassal

Bog Hoodlums

Bog Hoodlums can't block.
When Bog Hoodlums enters, clash with an opponent. If you win, put a +1/+1 counter on Bog Hoodlums. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)