Frightcrawler

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Threshold — As long as seven or more cards are in your graveyard, Frightcrawler gets +2/+2 and can't block.

Shadowblood Egg

{2}, {T}, Sacrifice Shadowblood Egg: Add {B}{R}. Draw a card.

Halberdier

Ghastly Demise

Destroy target nonblack creature if its toughness is less than or equal to the number of cards in your graveyard.

Famished Ghoul

{1}{B}, Sacrifice Famished Ghoul: Exile up to two target cards from a single graveyard.

Ravaged Highlands

Ravaged Highlands enters tapped.
{T}: Add {R}.
{T}, Sacrifice Ravaged Highlands: Add one mana of any color.

Bog Wreckage

Bog Wreckage enters tapped.
{T}: Add {B}.
{T}, Sacrifice Bog Wreckage: Add one mana of any color.

Cabal Pit

{T}: Add {B}. Cabal Pit deals 1 damage to you.
Threshold — {B}, {T}, Sacrifice Cabal Pit: Target creature gets -2/-2 until end of turn. Activate only if seven or more cards are in your graveyard.

Chainflinger

{1}{R}, {T}: Chainflinger deals 1 damage to any target.
Threshold — {2}{R}, {T}: Chainflinger deals 2 damage to any target. Activate only if seven or more cards are in your graveyard.

Childhood Horror

Flying
Threshold — As long as seven or more cards are in your graveyard, Childhood Horror gets +2/+2 and can't block.

Pardic Firecat

Haste
If Pardic Firecat is in a graveyard, effects from spells named Flame Burst count it as a card named Flame Burst.

Swamp

Reckless Charge

Target creature gets +3/+0 and gains haste until end of turn.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Braids, Cabal Minion

At the beginning of each player's upkeep, that player sacrifices an artifact, creature, or land of their choice.

Thermal Blast

Thermal Blast deals 3 damage to target creature.
Threshold — Thermal Blast deals 5 damage instead if seven or more cards are in your graveyard.

Barbarian Lunatic

{2}{R}, Sacrifice Barbarian Lunatic: It deals 2 damage to target creature.

Face of Fear

{2}{B}, Discard a card: Face of Fear gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Mountain

Crypt Creeper

Sacrifice Crypt Creeper: Exile target card from a graveyard.

Innocent Blood

Each player sacrifices a creature of their choice.

Firebolt

Firebolt deals 2 damage to any target.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Engulfing Flames

Engulfing Flames deals 1 damage to target creature. It can't be regenerated this turn.
Flashback {3}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Liquid Fire

As an additional cost to cast this spell, choose a number between 0 and 5.
Liquid Fire deals X damage to target creature and 5 minus X damage to that creature's controller, where X is the chosen number.

Morgue Theft

Return target creature card from your graveyard to your hand.
Flashback {4}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Flame Burst

Flame Burst deals X damage to any target, where X is 2 plus the number of cards named Flame Burst in all graveyards.

Dwarven Strike Force

Discard a card at random: Dwarven Strike Force gains first strike and haste until end of turn.

Morbid Hunger

Morbid Hunger deals 3 damage to any target. You gain 3 life.
Flashback {7}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Repentant Vampire

Flying
Whenever a creature dealt damage by Repentant Vampire this turn dies, put a +1/+1 counter on Repentant Vampire.
Threshold — As long as seven or more cards are in your graveyard, Repentant Vampire is white and has "{T}: Destroy target black creature."