Flying
Haunt (When this creature dies, exile it haunting target creature.)
When Blind Hunter enters the battlefield or the creature it haunts dies, target player loses 2 life and you gain 2 life.

Whenever you cast an instant or sorcery spell, Blistercoil Weird gets +1/+1 until end of turn. Untap it.

Trample, haste
At the beginning of the end step, Blitz Hellion's owner shuffles it into their library.

Flying
Whenever Blizzard Specter deals combat damage to a player, choose one —
• That player returns a permanent they control to its owner's hand.
• That player discards a card.

Target creature you control deals damage equal to its power to any target.
Fuse (You may cast one or both halves of this card from your hand.)

Lifelink, protection from white and from black
As long as you have 30 or more life and an opponent has 10 or less life, Blood Baron of Vizkopa gets +6/+6 and has flying.

: Blood Cultist deals 1 damage to target creature.
Whenever a creature dealt damage by Blood Cultist this turn dies, put a +1/+1 counter on Blood Cultist.

Flying, trample
At the beginning of your upkeep, each player loses 1 life. Put a +1/+1 counter on Blood Tyrant for each 1 life lost this way.
Whenever a player loses the game, put five +1/+1 counters on Blood Tyrant.

As long as you control an enchantment, Blood-Cursed Knight gets +1/+1 and has lifelink. (Damage dealt by this creature also causes you to gain that much life.)

Whenever a player casts a creature spell, each player returns all cards with the same name as that spell from their graveyard to the battlefield.

Haste
Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.)

Whenever Bloodhall Priest enters the battlefield or attacks, if you have no cards in hand, Bloodhall Priest deals 2 damage to any target.
Madness (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Flying
Bloodied Ghost enters the battlefield with a -1/-1 counter on it.

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Bloodwater Entity enters the battlefield, you may put target instant or sorcery card from your graveyard on top of your library.

Trample
Other red creatures you control get +1/+1.
Other green creatures you control get +1/+1.

Haste
Wither (This deals damage to creatures in the form of -1/-1 counters.)

, Remove a +1/+1 counter from a creature you control: Bolrac-Clan Crusher deals 2 damage to any target.

Flying
Whenever another creature enters the battlefield under your control, target creature gets +2/+0 until end of turn.

Mutate (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, return target permanent card from your graveyard to your hand.

Trample
Whenever Borborygmos deals combat damage to a player, put a +1/+1 counter on each creature you control.