Tomb Robber

Menace
{1}, Discard a card: Tomb Robber explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Tortured Existence

{B}, Discard a creature card: Return target creature card from your graveyard to your hand.

Call the Bloodline

{1}, Discard a card: Create a 1/1 black Vampire Knight creature token with lifelink. Activate only once each turn.

Mercenary Knight

When Mercenary Knight enters, sacrifice it unless you discard a creature card.

Inherited Fiend

Flying
{2}{B}: Exile target creature card from a graveyard. Put a +1/+1 counter on Inherited Fiend.

Heirloom Mirror

{1}, {T}, Pay 1 life, Discard a card: Draw a card, mill a card, then put a ritual counter on Heirloom Mirror. Then if it has three or more ritual counters on it, remove them and transform it. Activate only as a sorcery.

Heirloom Mirror // Inherited Fiend

Ashnod's Altar

Urborg Syphon-Mage

{2}{B}, {T}, Discard a card: Each other player loses 2 life. You gain life equal to the life lost this way.

Plague Witch

{B}, {T}, Discard a card: Target creature gets -1/-1 until end of turn.

Haakon, Stromgald Scourge

You may cast Haakon, Stromgald Scourge from your graveyard, but not from anywhere else.
As long as Haakon is on the battlefield, you may cast Knight spells from your graveyard.
When Haakon dies, you lose 2 life.

Necromancer's Stockpile

{1}{B}, Discard a creature card: Draw a card. If the discarded card was a Zombie card, create a tapped 2/2 black Zombie creature token.

Campfire

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

Command Beacon

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

Yawgmoth, Thran Physician

Protection from Humans
Pay 1 life, Sacrifice another creature: Put a -1/-1 counter on up to one target creature and draw a card.
{B}{B}, Discard a card: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Netherborn Altar

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

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)