msem-instigator

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Blood Servant enters, if it engorged a creature card, you draw a card and you lose 2 life.

{1}{B}, Sacrifice another creature, Discard two cards: Search your library for a card, put that card into your hand, then shuffle.

As an additional cost to cast this spell, sacrifice a creature.
Return a creature card from your graveyard to the battlefield, then return another creature card from your graveyard to your hand.

Target creature gets -4/-4 until end of turn. If that creature would die this turn, exile it instead.
Cycling {2} ({2}, Discard this card: Draw a card.)

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Blood-Tithe Harpy enters, target player loses 1 life and you gain 1 life.

Lifelink
{1}{B}, Sacrifice Bloodbond Ritualist: Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

{B}, Discard a card: Bloodbraid Ritualist gains indestructible until end of turn. Tap it.
At the beginning of your upkeep, you may have Bloodbraid Ritualist consume. If you do, draw a card. (To consume, sacrifice another creature or exile a creature card from your graveyard.)

When Bloodbriar Acolyte dies, draw a card. Each opponent loses 1 life.

Enchant creature
When Bloodbriar Blessing enters, draw a card.
Enchanted creature gets +2/+2 and has menace.

Flash (You may cast this spell any time you could cast an instant.)
When Bloodhunter Orca enters, target opponent sacrifices a creature that was dealt damage this turn.

{1}, {T}, Sacrifice another creature: Put a +1/+1 counter on Bloodied Wulfhound.

Sacrifice a creature: Put a +1/+1 counter on Bloodlash Caravan. Then if it's the only creature you control, it gains indestructible until end of turn.

Bloodleaf Butcher gets +1/+0 and has deathtouch as long as five or more cards are in your graveyard.

Deathtouch

Bloodline Zealot gets +2/+0 and has menace as long as you've sacrificed a permanent this turn.

When Bloodpact Collector enters, destroy target creature an opponent controls that was dealt damage this turn or has a -1/-1 counter on it.

When Bloodpact Tormentor enters, you may put a -1/-1 counter on target creature.
Bloodpact Tormentor can't be blocked by creatures with counters on them.

Flying
{1}, Sacrifice another creature: Regenerate target Vampire.

Enchant land
Enchanted land has “{T}: Each opponent loses 2 life.”

Flash
This spell costs {2} less to cast if five or more cards are in your graveyard.

Haste
Bloodvenge Berserker doesn't untap during its controller's untap step.
Once each turn, when an opponent is dealt damage by another source you control, you may untap Bloodvenge Berserker.

Whenever a creature dies, put a +1/+1 counter on Bog Apex.

When target creature dies this turn, return it to the battlefield under its owner's control. When you do, germinate. (Put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

At the beginning of your upkeep, you may pay 3 life. If you do, create a 2/1 red Lizard creature token with frenzy 2. (Whenever it attacks and isn't blocked, it gets +2/+0 until end of turn.)