Jet Medallion

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

Platinum Angel

Flying
You can't lose the game and your opponents can't win the game.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Sundial of the Infinite

{1}, {T}: End the turn. Activate only during your turn. (Exile all spells and abilities from the stack. Discard down to your maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Netherborn Altar

{T}, Put a soul counter on this artifact: Put your commander into your hand from the command zone. Then you lose 3 life for each soul counter on this artifact.

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik.

Campfire

{1}, {T}: You gain 2 life.
{2}, {T}, Exile this artifact: Put all commanders you own from the command zone and from your graveyard into your hand. Then shuffle your graveyard into your library.

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice this land: Put your commander into your hand from the command zone.

Phage the Untouchable

When Phage enters, if you didn't cast it from your hand, you lose the game.
Whenever Phage deals combat damage to a creature, destroy that creature. It can't be regenerated.
Whenever Phage deals combat damage to a player, that player loses the game.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Torpor Orb

Creatures entering don't cause abilities to trigger.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Trailblazer's Boots

Equipped creature has nonbasic landwalk. (It can't be blocked as long as defending player controls a nonbasic land.)
Equip {2}

Gray Merchant of Asphodel

When this creature enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}