Rakdos Signet

The Cruelty of Gix

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — Target opponent reveals their hand. You choose a creature or planeswalker card from it. That player discards that card.
II — Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.
III — Put target creature card from a graveyard onto the battlefield under your control.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Hurl Through Hell

Exile target creature. Until the end of your next turn, you may cast that card and you may spend mana as though it were mana of any color to cast that spell.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Terminate

Destroy target creature. It can't be regenerated.

Xathrid Demon

Flying, trample
At the beginning of your upkeep, sacrifice a creature other than Xathrid Demon, then each opponent loses life equal to the sacrificed creature's power. If you can't sacrifice a creature, tap Xathrid Demon and you lose 7 life.

Restless Vents

Restless Vents enters tapped.
{T}: Add {B} or {R}.
{1}{B}{R}: Until end of turn, Restless Vents becomes a 2/3 black and red Insect creature with menace. It's still a land.
Whenever Restless Vents attacks, you may discard a card. If you do, draw a card.

Mizzium Mortars

Mizzium Mortars deals 4 damage to target creature you don't control.
Overload {3}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Grim Tutor

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.

Boltwave

Boltwave deals 3 damage to each opponent.

Swamp

Bloodstained Mire

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Ob Nixilis of the Black Oath

+2: Each opponent loses 1 life. You gain life equal to the life lost this way.
−2: Create a 5/5 black Demon creature token with flying. You lose 2 life.
−8: You get an emblem with "{1}{B}, Sacrifice a creature: You gain X life and draw X cards, where X is the sacrificed creature's power."
Ob Nixilis of the Black Oath can be your commander.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Blackcleave Cliffs

Blackcleave Cliffs enters tapped unless you control two or fewer other lands.
{T}: Add {B} or {R}.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Sol Ring

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Jet Medallion

Black spells you cast cost {1} less to cast.

Malignus

Malignus's power and toughness are each equal to half the highest life total among your opponents, rounded up.
Damage that would be dealt by Malignus can't be prevented.

Mountain

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Wound Reflection

At the beginning of each end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)