Free-for-All

When Free-for-All enters, exile all creatures face down.
At the beginning of each player's upkeep, that player chooses a card exiled with Free-for-All at random and puts it onto the battlefield.
When Free-for-All leaves the battlefield, put all cards exiled with it into their owners' graveyards.

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.

Staying Power

"Until end of turn" and "this turn" effects don't end.

Ayara, First of Locthwain

Whenever Ayara, First of Locthwain or another black creature you control enters, each opponent loses 1 life and you gain 1 life.
{T}, Sacrifice another black creature: Draw a card.

Sign in Blood

Target player draws two cards and loses 2 life.

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Shadowborn Apostle

A deck can have any number of cards named Shadowborn Apostle.
{B}, Sacrifice six creatures named Shadowborn Apostle: Search your library for a Demon creature card, put it onto the battlefield, then shuffle.

Dark Ritual

Vilis, Broker of Blood

Flying
{B}, Pay 2 life: Target creature gets -1/-1 until end of turn.
Whenever you lose life, draw that many cards. (Damage causes loss of life.)

Ineffable Blessing

As Ineffable Blessing enters, choose white-bordered or silver-bordered.
Whenever a creature you control with the chosen border enters, draw a card.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Swamp

Carnival of Souls

Whenever a creature enters, you lose 1 life and add {B}.

B-I-N-G-O

Trample
Whenever a player casts a spell, put a chip counter on its mana value.
B-I-N-G-O gets +9/+9 for each set of three numbers in a row with chip counters on them.

Peer into the Abyss

Target player draws cards equal to half the number of cards in their library and loses half their life. Round up each time.

Demon of Death's Gate

You may pay 6 life and sacrifice three black creatures rather than pay this spell's mana cost.
Flying, trample

Echoing Return

Return target creature card and all other cards with the same name as that card from your graveyard to your hand.

Incoming!

Each player searches their library for any number of artifact, creature, enchantment, and/or land cards, puts them onto the battlefield, then shuffles.