Activate Warren Soultrader by paying 1 life and sacrificing Gravecrawler.
When Gravecrawler dies, Grave Venerations triggers, causing you to gain 1 life and target opponent to lose 1 life.
Resolve the Warren Soultrader ability, creating a Treasure token.
Activate the Treasure by tapping and sacrificing it, adding {B}.
Cast Gravecrawler from your graveyard by paying {B}.
Repeat.

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Infinite death triggers

Infinite lifegain triggers

Infinite lifeloss

Infinite storm count

Warren Soultrader

Gravecrawler

Grave Venerations

Activate Warren Soultrader by paying 1 life and sacrificing Reassembling Skeleton.
When Reassembling Skeleton dies, Grave Venerations and Pitiless Plunderer trigger.
Resolve the Grave Venerations trigger, causing you to gain 1 life and each opponent to lose 1 life.
Resolve the Pitiless Plunderer trigger, creating a Treasure token.
Resolve the Warren Soultrader ability, creating a Treasure token.
Activate the Treasures by tapping and sacrificing them, adding {1}{B}.
Activate Reassembling Skeleton by paying {1}{B}, returning it from your graveyard to the battlefield.
Repeat.

Infinite artifact ETB

Infinite artifact LTB

Infinite artifact sacrifice triggers

Pitiless Plunderer

Reassembling Skeleton

Activate Phyrexian Altar by sacrificing the one-drop creature, adding {B}.
When that creature dies, it and Grave Venerations trigger.
Resolve the creature's ability, creating a creature token.
Resolve the Grave Venerations ability, gaining at least one life and causing at least one opponent to lose at least one life.
When you gain life, Veinwitch Coven triggers, causing you to pay {B} to return the one-drop creature from your graveyard to your hand.
Activate Phyrexian Altar by sacrificing the token creature, adding one colored mana.
Cast the creature by paying one mana.
Repeat.

Infinite lifegain

One-drop creature with a second body

Veinwitch Coven

Phyrexian Altar

Activate Phyrexian Altar by sacrificing the creature castable for {0}, adding {B}.
When that creature dies, Grave Venerations triggers, causing you to gain 1 life and each opponent to lose 1 life.
When you gain life, Veinwitch Coven triggers, causing you to pay {B} to return the sacrificed creature from your graveyard to your hand.
Cast that creature by paying {0}.
Repeat.

Creature castable for {0} that survives

Cast Blood Pet by paying its mana cost.
Activate Blood Pet by sacrificing it.
When Blood Pet dies, Mortuary and Grave Venerations trigger.
Resolve the Mortuary trigger, putting Blood Pet from your graveyard onto the top of your library.
Resolve the Grave Venerations trigger, causing each opponent to lose 1 life and you to gain 1 life.
Cast Blood Pet from the top of your library by paying 1 life.
Repeat from step 2.

Infinite black mana

Mortuary

Blood Pet

Gwenom, Remorseless

Activate Chainer by paying {B}{B}{B} and 3 life, returning Grave Titan from your graveyard to the battlefield.
When Grave Titan enters, it triggers, creating two 2/2 Zombie creature tokens.
Activate Phyrexian Altar three times by sacrificing Grave Titan and the two Zombies, adding {B}{B}{B}
When Grave Titan and the Zombie tokens die, Grave Venerations triggers three times, causing you to gain 1 life and each opponent to lose 1 life for each trigger.
Repeat.

Chainer, Dementia Master

Grave Titan

Activate Unfulfilled Desires by paying {1} and 1 life, causing you to loot.
The Locust God triggers, creating a 1/1 Insect creature token with flying and haste.
Activate Phyrexian Altar by sacrificing the Insect, adding one mana of any color
When the Insect dies, Grave Venerations triggers, causing you to gain 1 life and each opponent to lose 1 life.
Repeat.

Combos with "Grave Venerations"