Ghost Tactician

{W}, {T}, Discard a card: Creatures you control get +1/+0 until end of turn.

Advanced Stitchwing

Flying
{2}{U}, Discard two cards: Return this card from your graveyard to the battlefield tapped.

Cabal Initiate

Discard a card: This creature gains lifelink until end of turn.
Threshold — This creature gets +1/+2 as long as seven or more cards are in your graveyard.

Putrid Imp

Discard a card: This creature gains flying until end of turn.
Threshold — As long as seven or more cards are in your graveyard, this creature gets +1/+1 and can't block.

Pardic Lancer

Discard a card at random: This creature gets +1/+0 and gains first strike until end of turn.

Resilient Wanderer

First strike
Discard a card: This creature gains protection from the color of your choice until end of turn.

Homicidal Brute

At the beginning of your end step, if this creature didn't attack this turn, tap this creature, then transform it.

Civilized Scholar

{T}: Draw a card, then discard a card. If a creature card is discarded this way, untap this creature, then transform it.

Civilized Scholar // Homicidal Brute

Stern Constable

{T}, Discard a card: Tap target creature.

Firefright Mage

{1}{R}, {T}, Discard a card: Target creature can't be blocked this turn except by artifact creatures and/or red creatures.

Hapless Researcher

Sacrifice this creature: Draw a card, then discard a card.

Devout Witness

{1}{W}, {T}, Discard a card: Destroy target artifact or enchantment.

Obsessive Astronomer

If it's neither day nor night, it becomes day as this creature enters.
Whenever day becomes night or night becomes day, discard up to two cards, then draw that many cards.

Eyetwitch

Flying
When this creature dies, learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Fleeting Spirit

{W}, Exile three cards from your graveyard: This creature gains first strike until end of turn.
Discard a card: Exile this creature. Return it to the battlefield under its owner's control at the beginning of the next end step.

Reckless Scholar

{T}: Target player draws a card, then discards a card.

Stampede Driver

{1}{G}, {T}, Discard a card: Creatures you control get +1/+1 and gain trample until end of turn.

Ghoulsteed

{2}{B}, Discard two cards: Return this card from your graveyard to the battlefield tapped.

Irreverent Gremlin

Menace (This creature can't be blocked except by two or more creatures.)
Whenever another creature you control with power 2 or less enters, you may discard a card. If you do, draw a card. Do this only once each turn.

Haunted Dead

When this creature enters, create a 1/1 white Spirit creature token with flying.
{1}{B}, Discard two cards: Return this card from your graveyard to the battlefield tapped.

Mad Prophet

Furyblade Vampire

Trample
At the beginning of combat on your turn, you may discard a card. If you do, this creature gets +3/+0 until end of turn.

Inherited Fiend

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

Heirloom Mirror

{1}, {T}, Pay 1 life, Discard a card: Draw a card, mill a card, then put a ritual counter on this artifact. 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

Belligerent Guest

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever this creature deals combat damage to a player, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")

Wild Mongrel

Discard a card: This creature gets +1/+1 and becomes the color of your choice until end of turn.

Ravenous Bloodseeker

Discard a card: This creature gets +2/-2 until end of turn.

Noose Constrictor

Reach
Discard a card: This creature gets +1/+1 until end of turn.

Tunneler Wurm

Discard a card: Regenerate this creature.

Transplant Theorist

Whenever this creature or another artifact you control enters, you may draw a card. If you do, discard a card.
{2}: Put target card from your graveyard on the bottom of your library.

Possessed Goat

{3}, Discard a card: Put three +1/+1 counters on this creature and it becomes a black Demon in addition to its other colors and types. Activate only once.

Heir to the Night

Heir of Falkenrath

Discard a card: Transform this creature. Activate only once each turn.

Heir of Falkenrath // Heir to the Night

Nantuko Cultivator

When this creature enters, you may discard any number of land cards. Put that many +1/+1 counters on this creature and draw that many cards.

Necromancer's Familiar

Flying
Hellbent — This creature has lifelink as long as you have no cards in hand.
{B}, Discard a card: This creature gains indestructible until end of turn. Tap it.

Aquamoeba

Discard a card: Switch this creature's power and toughness until end of turn.

Stitchwing Skaab

Flying
{1}{U}, Discard two cards: Return this card from your graveyard to the battlefield tapped.

Bonded Fetch

Defender, haste
{T}: Draw a card, then discard a card.

Wasteland Viper

Deathtouch
Bloodrush — {G}, Discard this creature: Target attacking creature gets +1/+2 and gains deathtouch until end of turn.

Insolent Neonate

Menace (This creature can't be blocked except by two or more creatures.)
Discard a card, Sacrifice this creature: Draw a card.

Seasoned Hallowblade

Discard a card: Tap this creature. It gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Pack Guardian

Flash
When this creature enters, you may discard a land card. If you do, create a 2/2 green Wolf creature token.

Archive Haunt

Flying
Whenever this creature attacks, draw a card, then discard a card.
If Archive Haunt would be put into a graveyard from anywhere, exile it instead.

Overwhelmed Archivist

When this creature enters, draw a card, then discard a card.
Disturb {3}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Overwhelmed Archivist // Archive Haunt

Skywing Aven

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

Thraben Standard Bearer

{1}{W}, {T}, Discard a card: Create a 1/1 white Human Soldier creature token.

Fa'adiyah Seer

{T}: Draw a card and reveal it. If it isn't a land card, discard it.

Sanctum Spirit

Lifelink
Discard a historic card: This creature gains indestructible until end of turn. (Artifacts, legendaries, and Sagas are historic.)

Crashing Centaur

{G}, Discard a card: This creature gains trample until end of turn.
Threshold — As long as seven or more cards are in your graveyard, this creature gets +2/+2 and has shroud. (It can't be the target of spells or abilities.)

Ridged Kusite

{1}{B}, {T}, Discard a card: Target creature gets +1/+0 and gains first strike until end of turn.

Rushwood Herbalist

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

Splitskin Doll

When this creature enters, draw a card. Then discard a card unless you control another creature with power 2 or less.

Osseous Sticktwister

Lifelink
Delirium — At the beginning of your end step, if there are four or more card types among cards in your graveyard, each opponent may sacrifice a nonland permanent of their choice or discard a card. Then this creature deals damage equal to its power to each opponent who didn't sacrifice a permanent or discard a card this way.

Burning-Fist Minotaur

First strike
{1}{R}, Discard a card: This creature gets +2/+0 until end of turn.