Thalakos Drifters

Discard a card: Thalakos Drifters gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)

Oblivion Crown

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature has "Discard a card: This creature gets +1/+1 until end of turn."

Sins of the Past

Until end of turn, you may cast target instant or sorcery card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead. Exile Sins of the Past.

Army of the Damned

Create thirteen tapped 2/2 black Zombie creature tokens.
Flashback {7}{B}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Graveyard Shift

This spell has flash as long as there are five or more mana values among cards in your graveyard.
Return target creature card from your graveyard to the battlefield.

Oskar, Rubbish Reclaimer

This spell costs {1} less to cast for each different mana value among cards in your graveyard.
Whenever you discard a nonland card, you may cast it from your graveyard.

Behold the Beyond

Discard your hand. Search your library for three cards, put them into your hand, then shuffle.

The Underworld Cookbook

{T}, Discard a card: Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
{4}, {T}, Sacrifice The Underworld Cookbook: Return target creature card from your graveyard to your hand.

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

Key to the City

{T}, Discard a card: Up to one target creature can't be blocked this turn.
Whenever Key to the City becomes untapped, you may pay {2}. If you do, draw a card.

Bog Witch

Insidious Mist

Hexproof, indestructible
Insidious Mist can't block and can't be blocked.
Whenever Insidious Mist attacks and isn't blocked, you may pay {2}{B}. If you do, transform it.

Elusive Tormentor

{1}, Discard a card: Transform Elusive Tormentor.

Elusive Tormentor // Insidious Mist

Invoke the Winds

Gain control of target artifact or creature. Untap it.

Cryptbreaker

{1}{B}, {T}, Discard a card: Create a 2/2 black Zombie creature token.
Tap three untapped Zombies you control: You draw a card and you lose 1 life.

Psychatog

Discard a card: Psychatog gets +1/+1 until end of turn.
Exile two cards from your graveyard: Psychatog gets +1/+1 until end of turn.

Undertaker

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

Mnemonic Deluge

Exile target instant or sorcery card from a graveyard. Copy that card three times. You may cast the copies without paying their mana costs. Exile Mnemonic Deluge.

Undead Gladiator

{1}{B}, Discard a card: Return Undead Gladiator from your graveyard to your hand. Activate only during your upkeep.
Cycling {1}{B} ({1}{B}, Discard this card: Draw a card.)

Skirge Familiar

Diplomatic Escort

{U}, {T}, Discard a card: Counter target spell or ability that targets a creature.

Oona's Prowler

Flying
Discard a card: Oona's Prowler gets -2/-0 until end of turn. Any player may activate this ability.

Rise of the Dark Realms

Put all creature cards from all graveyards onto the battlefield under your control.

Pack Rat

Pack Rat's power and toughness are each equal to the number of Rats you control.
{2}{B}, Discard a card: Create a token that's a copy of Pack Rat.

Aeromoeba

Flying
Discard a card: Switch Aeromoeba's power and toughness until end of turn.

Choice of Damnations

Target opponent chooses a number. You may have that player lose that much life. If you don't, that player sacrifices all but that many permanents of their choice.

Riches

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Each opponent chooses a creature they control. You gain control of those creatures.

Rags

All creatures get -2/-2 until end of turn.

Rags // Riches

Decree of Pain

Destroy all creatures. They can't be regenerated. Draw a card for each creature destroyed this way.
Cycling {3}{B}{B} ({3}{B}{B}, Discard this card: Draw a card.)
When you cycle Decree of Pain, all creatures get -2/-2 until end of turn.

Ambition's Cost

You draw three cards and you lose 3 life.

Mortiphobia

{1}{B}, Discard a card: Exile target card from a graveyard.
{1}{B}, Sacrifice Mortiphobia: Exile target card from a graveyard.

Trickster Mage

{U}, {T}, Discard a card: You may tap or untap target artifact, creature, or land.

Stronghold Machinist

{U}{U}, {T}, Discard a card: Counter target noncreature spell.

Compulsion

{1}{U}, Discard a card: Draw a card.
{1}{U}, Sacrifice Compulsion: Draw a card.

Deny Reality

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 in a random order.)
Return target permanent to its owner's hand.

Scuttletide

{1}, Discard a card: Create a 0/3 blue Crab creature token.
Delirium — Crabs you control get +1/+1 as long as there are four or more card types among cards in your graveyard.

Waterfront Bouncer

{U}, {T}, Discard a card: Return target creature to its owner's hand.

Mental Discipline

Grimoire of the Dead

{1}, {T}, Discard a card: Put a study counter on Grimoire of the Dead.
{T}, Remove three study counters from Grimoire of the Dead and sacrifice it: Put all creature cards from all graveyards onto the battlefield under your control. They're black Zombies in addition to their other colors and types.

Denying Wind

Search target player's library for up to seven cards and exile them. Then that player shuffles.

Boneyard Parley

Exile up to five target creature cards from graveyards. An opponent separates those cards into two piles. Put all cards from the pile of your choice onto the battlefield under your control and the rest into their owners' graveyards.

Escape Artist

Escape Artist can't be blocked.
{U}, Discard a card: Return Escape Artist to its owner's hand.

Ephemeron

Flying
Discard a card: Return Ephemeron to its owner's hand.

Prognostic Sphinx

Flying
Discard a card: Prognostic Sphinx gains hexproof until end of turn. Tap it.
Whenever Prognostic Sphinx attacks, scry 3.

Mind Over Matter

Discard a card: You may tap or untap target artifact, creature, or land.

Mindless Automaton

Mindless Automaton enters with two +1/+1 counters on it.
{1}, Discard a card: Put a +1/+1 counter on Mindless Automaton.
Remove two +1/+1 counters from Mindless Automaton: Draw a card.

Ghostly Wings

Enchant creature
Enchanted creature gets +1/+1 and has flying.
Discard a card: Return enchanted creature to its owner's hand.

Medicine Bag

{1}, {T}, Discard a card: Regenerate target creature.

Trading Post

{1}, {T}, Discard a card: You gain 4 life.
{1}, {T}, Pay 1 life: Create a 0/1 white Goat creature token.
{1}, {T}, Sacrifice a creature: Return target artifact card from your graveyard to your hand.
{1}, {T}, Sacrifice an artifact: Draw a card.

Necromantic Selection

Destroy all creatures, then return a creature card put into a graveyard this way to the battlefield under your control. It's a black Zombie in addition to its other colors and types. Exile Necromantic Selection.

Ghostly Pilferer

Whenever Ghostly Pilferer becomes untapped, you may pay {2}. If you do, draw a card.
Whenever an opponent casts a spell from anywhere other than their hand, draw a card.
Discard a card: Ghostly Pilferer can't be blocked this turn.

Olivia's Dragoon

Discard a card: Olivia's Dragoon gains flying until end of turn.

Stronghold Biologist

{U}{U}, {T}, Discard a card: Counter target creature spell.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Call the Bloodline

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