Deal Gone Bad

Target creature gets -3/-3 until end of turn. Target player mills three cards. (They put the top three cards of their library into their graveyard.)

Goremand

As an additional cost to cast this spell, sacrifice a creature.
Flying
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
When Goremand enters, each opponent sacrifices a creature.

Undead Butler

When Undead Butler enters, mill three cards. (Put the top three cards of your library into your graveyard.)
When Undead Butler dies, you may exile it. When you do, return target creature card from your graveyard to your hand.

Thriving Moor

Thriving Moor enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Persistent Specimen

{2}{B}: Return Persistent Specimen from your graveyard to the battlefield tapped.

Eternal Taskmaster

Eternal Taskmaster enters tapped.
Whenever Eternal Taskmaster attacks, you may pay {2}{B}. If you do, return target creature card from your graveyard to your hand.

Gorging Vulture

Flying
When Gorging Vulture enters, mill four cards. You gain 1 life for each creature card milled this way. (To mill four cards, put the top four cards of your library into your graveyard.)

Murder

Revoke Demise

This spell costs {2} less to cast if it targets a creature card with mana value 3 or less.
Return target creature card from your graveyard to the battlefield. You gain 2 life.

Shardless Outlander

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Basic landcycling {2} ({2}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Swamp

Isareth the Awakener

Deathtouch
Whenever Isareth the Awakener attacks, you may pay {X}. When you do, return target creature card with mana value X from your graveyard to the battlefield with a corpse counter on it. If that creature would leave the battlefield, exile it instead of putting it anywhere else.

Gravedigger

When Gravedigger enters, you may return target creature card from your graveyard to your hand.

Liliana, Death's Majesty

+1: Create a 2/2 black Zombie creature token. Mill two cards.
−3: Return target creature card from your graveyard to the battlefield. That creature is a black Zombie in addition to its other colors and types.
−7: Destroy all non-Zombie creatures.