Putrid Imp

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

Diabolic Servitude

When Diabolic Servitude enters, return target creature card from your graveyard to the battlefield.
When the creature put onto the battlefield with Diabolic Servitude dies, exile it and return Diabolic Servitude to its owner's hand.
When Diabolic Servitude leaves the battlefield, exile the creature put onto the battlefield with Diabolic Servitude.

Sickening Dreams

As an additional cost to cast this spell, discard X cards.
Sickening Dreams deals X damage to each creature and each player.

Hidden Horror

When Hidden Horror enters, sacrifice it unless you discard a creature card.

Blazing Archon

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Sphinx of the Steel Wind

Flying, first strike, vigilance, lifelink, protection from red and from green

Faceless Butcher

When Faceless Butcher enters, exile another target creature.
When Faceless Butcher leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Last Rites

Discard any number of cards. Target player reveals their hand, then you choose a nonland card from it for each card discarded this way. That player discards those cards.

Iona, Shield of Emeria

Flying
As Iona, Shield of Emeria enters, choose a color.
Your opponents can't cast spells of the chosen color.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Swamp

Avacyn, Angel of Hope

Flying, vigilance, indestructible
Other permanents you control have indestructible.

Inkwell Leviathan

Trample
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Shroud (This creature can't be the target of spells or abilities.)

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Strongarm Tactics

Each player discards a card. Then each player who didn't discard a creature card this way loses 4 life.

Dark Ritual

Akroma, Angel of Wrath

Flying, first strike, vigilance, trample, haste, protection from black and from red

Entomb

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