Enduring Tenacity

Whenever you gain life, target opponent loses that much life.
When Enduring Tenacity dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Phyrexian Vivisector

Whenever a creature you control dies, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Infestation Sage

When this creature dies, create a 1/1 black and green Insect creature token with flying.

Swamp

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Sengir Connoisseur

Flying
Whenever one or more other creatures die, put a +1/+1 counter on this creature. This ability triggers only once each turn.

Gibbering Barricade

Defender
{2}{B}, Sacrifice a creature: You gain 1 life and draw a card.

Smothering Abomination

Devoid (This card has no color.)
Flying
At the beginning of your upkeep, sacrifice a creature.
Whenever you sacrifice a creature, draw a card.

Vraan, Executioner Thane

Whenever one or more other creatures you control die, each opponent loses 2 life and you gain 2 life. This ability triggers only once each turn.

Defenestrate

Sanguine Syphoner

Whenever this creature attacks, each opponent loses 1 life and you gain 1 life.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Lively Dirge

Spree (Choose one or more additional costs.)
+ {1} — Search your library for a card, put it into your graveyard, then shuffle.
+ {2} — Return up to two creature cards with total mana value 4 or less from your graveyard to the battlefield.

Sinkhole Surveyor

Flying
Whenever this creature attacks, you lose 1 life and this creature endures 1. (Put a +1/+1 counter on it or create a 1/1 white Spirit creature token.)

Annihilating Glare

As an additional cost to cast this spell, pay {4} or sacrifice an artifact or creature.
Destroy target creature or planeswalker.

Kothophed, Soul Hoarder

Flying
Whenever a permanent owned by another player is put into a graveyard from the battlefield, you draw a card and you lose 1 life.

Village Rites

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

Morkrut Behemoth

As an additional cost to cast this spell, sacrifice a creature or pay {1}{B}.
Menace (This creature can't be blocked except by two or more creatures.)

Dross Skullbomb

{1}, Sacrifice this artifact: Draw a card.
{2}{B}, Sacrifice this artifact: Return target creature card from your graveyard to your hand. Draw a card. Activate only as a sorcery.

Archfiend of the Dross

Flying
This creature enters with four oil counters on it.
At the beginning of your upkeep, remove an oil counter from this creature. Then if it has no oil counters on it, you lose the game.
Whenever a creature an opponent controls dies, its controller loses 2 life.

Arbiter of Woe

As an additional cost to cast this spell, sacrifice a creature.
Flying
When this creature enters, each opponent discards a card and loses 2 life. You draw a card and gain 2 life.