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.

Demonic Tutor

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

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."

Grotesque Hybrid

Whenever this creature deals combat damage to a creature, destroy that creature. It can't be regenerated.
Discard a card: This creature gains flying and protection from green and from white until end of turn.

Dakmor Salvage

This land enters tapped.
{T}: Add {B}.
Dredge 2 (If you would draw a card, you may mill two cards instead. If you do, return this card from your graveyard to your hand.)

Trespasser il-Vec

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

Tunneler Wurm

Discard a card: Regenerate this creature.

Abundance

If you would draw a card, you may instead choose land or nonland and reveal cards from the top of your library until you reveal a card of the chosen kind. Put that card into your hand and put all other cards revealed this way on the bottom of your library in any order.

Ayula's Influence

Discard a land card: Create a 2/2 green Bear creature token.

Goblin Charbelcher

{3}, {T}: Reveal cards from the top of your library until you reveal a land card. This artifact deals damage equal to the number of nonland cards revealed this way to any target. If the revealed land card was a Mountain, this artifact deals double that damage instead. Put the revealed cards on the bottom of your library in any order.

Earsplitting Rats

When this creature enters, each player discards a card.
Discard a card: Regenerate this creature.

Oona's Prowler

Flying
Discard a card: This creature gets -2/-0 until end of turn. Any player may activate this ability.

The Gitrog Monster

Deathtouch
At the beginning of your upkeep, sacrifice The Gitrog Monster unless you sacrifice a land.
You may play an additional land on each of your turns.
Whenever one or more land cards are put into your graveyard from anywhere, draw a card.

Skirge Familiar

Epic Struggle

At the beginning of your upkeep, if you control twenty or more creatures, you win the game.