Lasyd Prowler

When this creature enters, you may mill cards equal to the number of lands you control.
Renew — {1}{G}, Exile this card from your graveyard: Put X +1/+1 counters on target creature, where X is the number of land cards in your graveyard. Activate only as a sorcery.

Naga Fleshcrafter

You may have this creature enter as a copy of any creature on the battlefield.
Renew — {2}{U}, Exile this card from your graveyard: Put a +1/+1 counter on target nonlegendary creature you control. Each other creature you control becomes a copy of that creature until end of turn. Activate only as a sorcery.

Carrionette

{2}{B}{B}: Exile this card and target creature unless that creature's controller pays {2}. Activate only if this card is in your graveyard.

Wretched Bonemass

Wretched Bonemass's power and toughness are each equal to the total power of the exiled cards used to craft it.
This creature has flying as long as an exiled card used to craft it has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, and vigilance.

Altar of the Wretched

When this artifact enters, you may sacrifice a nontoken creature. If you do, draw X cards, then mill X cards, where X is that creature's power.
Craft with one or more creatures {2}{B}{B}
{2}{B}: Return this card from your graveyard to your hand.

Altar of the Wretched // Wretched Bonemass

Ardyn, the Usurper

Demons you control have menace, lifelink, and haste.
Starscourge — At the beginning of combat on your turn, exile up to one target creature card from a graveyard. If you exiled a card this way, create a token that's a copy of that card, except it's a 5/5 black Demon.

Qarsi Revenant

Flying, deathtouch, lifelink
Renew — {2}{B}, Exile this card from your graveyard: Put a flying counter, a deathtouch counter, and a lifelink counter on target creature. Activate only as a sorcery.

Kheru Goldkeeper

Flying
Whenever one or more cards leave your graveyard during your turn, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Renew — {2}{B}{G}{U}, Exile this card from your graveyard: Put two +1/+1 counters and a flying counter on target creature. Activate only as a sorcery.

Rot-Curse Rakshasa

Trample
Decayed (This creature can't block. When it attacks, sacrifice it at end of combat.)
Renew — {X}{B}{B}, Exile this card from your graveyard: Put a decayed counter on each of X target creatures. Activate only as a sorcery.

Sage of the Fang

When this creature enters, put a +1/+1 counter on target creature.
Renew — {3}{G}, Exile this card from your graveyard: Put a +1/+1 counter on target creature, then double the number of +1/+1 counters on that creature. Activate only as a sorcery.