Stromkirk Bloodthief

At the beginning of your end step, if an opponent lost life this turn, put a +1/+1 counter on target Vampire you control.

Fiend of the Shadows

Flying
Whenever Fiend of the Shadows deals combat damage to a player, that player exiles a card from their hand. You may play that card for as long as it remains exiled.
Sacrifice a Human: Regenerate Fiend of the Shadows.

Blood Bairn

Sacrifice another creature: Blood Bairn gets +2/+2 until end of turn.

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.

Amalia Benavides Aguirre

Ward—Pay 3 life.
Whenever you gain life, Amalia Benavides Aguirre explores. Then destroy all other creatures if its power is exactly 20. (To have this creature explore, reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Child of Night

Blood Petal Celebrant

Blood Petal Celebrant has first strike as long as it's attacking. (It deals combat damage before creatures without first strike.)
When Blood Petal Celebrant dies, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")

Necropolis Regent

Flying
Whenever a creature you control deals combat damage to a player, put that many +1/+1 counters on it.

Belligerent Guest

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever Belligerent Guest deals combat damage to a player, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")

Markov Patrician

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

Rabid Bloodsucker

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Rabid Bloodsucker enters, each player loses 2 life.

Gluttonous Guest

When Gluttonous Guest enters, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Blood token, you gain 1 life.

Duskborne Skymarcher

Flying
{W}, {T}: Target attacking Vampire gets +1/+1 until end of turn.

Blood Hypnotist

Blood Hypnotist can't block.
Whenever you sacrifice one or more Blood tokens, target creature can't block this turn. This ability triggers only once each turn.

Teysa Karlov

If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Creature tokens you control have vigilance and lifelink.

Bold Plagiarist

Flash
Whenever an opponent puts one or more counters on a creature they control, they put the same number and kind of counters on Bold Plagiarist.

Vito's Inquisitor

{B}, Sacrifice another creature or artifact: Put a +1/+1 counter on Vito's Inquisitor. It gains menace until end of turn.

Bishop of Rebirth

Vigilance
Whenever Bishop of Rebirth attacks, you may return target creature card with mana value 3 or less from your graveyard to the battlefield.

Vampire of the Dire Moon

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)