Say Its Name

Mill three cards. Then you may return a creature or land card from your graveyard to your hand.
Exile this card and two other cards named Say Its Name from your graveyard: Search your graveyard, hand, and/or library for a card named Altanak, the Thrice-Called and put it onto the battlefield. If you search your library this way, shuffle. Activate only as a sorcery.

Possessed Goat

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

Doomsday Excruciator

Flying
When Doomsday Excruciator enters, if it was cast, each player exiles all but the bottom six cards of their library face down.
At the beginning of your upkeep, draw a card.

Seized from Slumber

This spell costs {3} less to cast if it targets a tapped creature.
Destroy target creature.

Manifest Dread

Manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Appendage Amalgam

Flash
Whenever Appendage Amalgam attacks, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Murder

Valgavoth, Terror Eater

Flying, lifelink
Ward—Sacrifice three nonland permanents.
If a card you didn't control would be put into an opponent's graveyard from anywhere, exile it instead.
During your turn, you may play cards exiled with Valgavoth. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.

Swamp

Cadaver Lab

When you unlock this door, return target creature card from your graveyard to your hand.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Defiled Crypt

Whenever one or more cards leave your graveyard, create a 2/2 black Horror enchantment creature token. This ability triggers only once each turn.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Defiled Crypt // Cadaver Lab

Demonic Counsel

Search your library for a Demon card, reveal it, put it into your hand, then shuffle.
Delirium — If there are four or more card types among cards in your graveyard, instead search your library for any card, put it into your hand, then shuffle.

Fear of Surveillance

Vigilance
Whenever Fear of Surveillance attacks, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Emerge from the Cocoon

Return target creature card from your graveyard to the battlefield. You gain 3 life.

Forest

Neglected Manor

Neglected Manor enters tapped unless a player has 13 or less life.
{T}: Add {W} or {B}.

Unsettling Twins

When Unsettling Twins enters, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Plains

Innocuous Rat

When Innocuous Rat dies, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)