Thief of Blood

Flying
As Thief of Blood enters the battlefield, remove all counters from all permanents. Thief of Blood enters the battlefield with a +1/+1 counter on it for each counter removed this way.

Vampire Cutthroat

Skulk (This creature can't be blocked by creatures with greater power.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Charmed Sleep

Enchant creature
When Charmed Sleep enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Dream Fighter

Whenever Dream Fighter blocks or becomes blocked by a creature, Dream Fighter and that creature phase out. (While they're phased out, they're treated as though they don't exist. Each one phases in before its controller untaps during their next untap step.)

Dreamscape Artist

{2}{U}, {T}, Discard a card, Sacrifice a land: Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Kazarov, Sengir Pureblood

Flying
Whenever a creature an opponent controls is dealt damage, put a +1/+1 counter on Kazarov, Sengir Pureblood.
{3}{R}: Kazarov deals 2 damage to target creature.

Cordial Vampire

Whenever Cordial Vampire or another creature dies, put a +1/+1 counter on each Vampire you control.

Stalking Vampire

At the beginning of your upkeep, you may pay {2}{B}{B}. If you do, transform Stalking Vampire.

Screeching Bat

Flying
At the beginning of your upkeep, you may pay {2}{B}{B}. If you do, transform Screeching Bat.

Screeching Bat // Stalking Vampire

Kediss, Emberclaw Familiar

Whenever a commander you control deals combat damage to an opponent, it deals that much damage to each other opponent.
Partner (You can have two commanders if both have partner.)

Grandmother Sengir

{1}{B}, {T}: Target creature gets -1/-1 until end of turn.

Falthis, Shadowcat Familiar

Commanders you control have menace and deathtouch.
Partner (You can have two commanders if both have partner.)

Send to Sleep

Tap up to two target creatures.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, those creatures don't untap during their controllers' next untap steps.

Sengir Nosferatu

Flying
{1}{B}, Exile Sengir Nosferatu: Create a 1/2 black Bat creature token with flying. It has "{1}{B}, Sacrifice this creature: Return an exiled card named Sengir Nosferatu to the battlefield under its owner's control."

Deathgrip

Castle Sengir

{T}: Add {C}.
{1}, {T}: Add {B}.
{2}, {T}: Add {U} or {R}.

Sleep of the Dead

Tap target creature. It doesn't untap during its controller's next untap step.
Escape—{2}{U}, Exile three other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

The Ozolith

Whenever a creature you control leaves the battlefield, if it had counters on it, put those counters on The Ozolith.
At the beginning of combat on your turn, if The Ozolith has counters on it, you may move all counters from The Ozolith onto target creature.

Sleep

Tap all creatures target player controls. Those creatures don't untap during that player's next untap step.

Insolent Neonate

Menace (This creature can't be blocked except by two or more creatures.)
Discard a card, Sacrifice Insolent Neonate: Draw a card.

Sleep Paralysis

Enchant creature
When Sleep Paralysis enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Baron Sengir

Flying
Whenever a creature dealt damage by Baron Sengir this turn dies, put a +2/+2 counter on Baron Sengir.
{T}: Regenerate another target Vampire.

Veldrane of Sengir

{1}{B}{B}: Veldrane of Sengir gets -3/-0 and gains forestwalk until end of turn. (It can't be blocked as long as defending player controls a Forest.)

Sengir Vampire

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a creature dealt damage by Sengir Vampire this turn dies, put a +1/+1 counter on Sengir Vampire.

Vampire Neonate

{2}, {T}: Each opponent loses 1 life and you gain 1 life.

Vampire Hexmage

First strike
Sacrifice Vampire Hexmage: Remove all counters from target permanent.

Havengul Vampire

Whenever Havengul Vampire deals combat damage to a player, put a +1/+1 counter on it.
Whenever another creature dies, put a +1/+1 counter on Havengul Vampire.

Dream Stalker

When Dream Stalker enters the battlefield, return a permanent you control to its owner's hand.

Sengir, the Dark Baron

Flying
Whenever another creature dies, put two +1/+1 counters on Sengir, the Dark Baron.
Whenever another player loses the game, you gain life equal to that player's life total as the turn began.
Partner (You can have two commanders if both have partner.)

Sleeper's Robe

Enchant creature
Enchanted creature has fear. (It can't be blocked except by artifact creatures and/or black creatures.)
Whenever enchanted creature deals combat damage to an opponent, you may draw a card.

Fate Transfer

Move all counters from target creature onto another target creature.

Dream Fracture

Counter target spell. Its controller draws a card.
Draw a card.

Sigil of Sleep

Enchant creature
Whenever enchanted creature deals damage to a player, return target creature that player controls to its owner's hand.

Vindictive Vampire

Whenever another creature you control dies, Vindictive Vampire deals 1 damage to each opponent and you gain 1 life.

Xantcha, Sleeper Agent

Xantcha, Sleeper Agent enters the battlefield under the control of an opponent of your choice.
Xantcha attacks each combat if able and can't attack its owner or planeswalkers its owner controls.
{3}: Xantcha's controller loses 2 life and you draw a card. Any player may activate this ability.

Sengir Bats

Flying
Whenever a creature dealt damage by Sengir Bats this turn dies, put a +1/+1 counter on Sengir Bats.

Skeletal Vampire

Flying
When Skeletal Vampire enters the battlefield, create two 1/1 black Bat creature tokens with flying.
{3}{B}{B}, Sacrifice a Bat: Create two 1/1 black Bat creature tokens with flying.
Sacrifice a Bat: Regenerate Skeletal Vampire.

Glimmerdust Nap

Enchant tapped creature
Enchanted creature doesn't untap during its controller's untap step.

Kraum, Ludevic's Opus

Flying, haste
Whenever an opponent casts their second spell each turn, draw a card.
Partner (You can have two commanders if both have partner.)

Sleeping Potion

Enchant creature
When Sleeping Potion enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.
When enchanted creature becomes the target of a spell or ability, sacrifice Sleeping Potion.

Captivating Vampire

Other Vampire creatures you control get +1/+1.
Tap five untapped Vampires you control: Gain control of target creature. It becomes a Vampire in addition to its other types.

Sengir Autocrat

When Sengir Autocrat enters the battlefield, create three 0/1 black Serf creature tokens.
When Sengir Autocrat leaves the battlefield, exile all Serf tokens.

Dream Devourer

Each nonland card in your hand without foretell has foretell. Its foretell cost is equal to its mana cost reduced by {2}. (During your turn, you may pay {2} and exile it from your hand face down. Cast it on a later turn for its foretell cost.)
Whenever you foretell a card, Dream Devourer gets +2/+0 until end of turn.

Sleeper Agent

When Sleeper Agent enters the battlefield, target opponent gains control of it.
At the beginning of your upkeep, Sleeper Agent deals 2 damage to you.