Rust Elemental

Flying
At the beginning of your upkeep, sacrifice an artifact other than Rust Elemental. If you can't, tap Rust Elemental and you lose 4 life.

Drinker of Sorrow

Drinker of Sorrow can't block.
Whenever Drinker of Sorrow deals combat damage, sacrifice a permanent.

Thrashing Mudspawn

Whenever Thrashing Mudspawn is dealt damage, you lose that much life.
Morph {1}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Go for the Throat

Ebon Drake

Flying
Whenever a player casts a spell, you lose 1 life.

Infernal Grasp

Destroy target creature. You lose 2 life.

The Watcher in the Water

The Watcher in the Water enters the battlefield tapped with nine stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you draw a card during an opponent's turn, create a 1/1 blue Tentacle creature token.
Whenever a Tentacle you control dies, untap up to one target Kraken and put a stun counter on up to one target nonland permanent.

Archfiend of the Dross

Flying
Archfiend of the Dross enters the battlefield with four oil counters on it.
At the beginning of your upkeep, remove an oil counter from Archfiend of the Dross. 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.

Rite of Belzenlok

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Create two 0/1 black Cleric creature tokens.
III — Create a 6/6 black Demon creature token with flying, trample, and "At the beginning of your upkeep, sacrifice another creature. If you can't, this creature deals 6 damage to you."

Fateful Handoff

Draw cards equal to the mana value of target artifact or creature you control. An opponent gains control of that permanent.

Blighted Agent

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Blighted Agent can't be blocked.

Parasitic Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, its controller loses 2 life and you gain 2 life.

Homeward Path

{T}: Add {C}.
{T}: Each player gains control of all creatures they own.

Staff of Compleation

{T}, Pay 1 life: Destroy target permanent you own.
{T}, Pay 2 life: Add one mana of any color.
{T}, Pay 3 life: Proliferate.
{T}, Pay 4 life: Draw a card.
{5}: Untap Staff of Compleation.

Morkrut Necropod

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Morkrut Necropod attacks or blocks, sacrifice another creature or land.

Sygg, River Cutthroat

At the beginning of each end step, if an opponent lost 3 or more life this turn, you may draw a card. (Damage causes loss of life.)

Greater Harvester

At the beginning of your upkeep, sacrifice a permanent.
Whenever Greater Harvester deals combat damage to a player, that player sacrifices two permanents.

Slither Blade

Hostile Negotiations

Exile the top three cards of your library in a face-down pile, then exile the top three cards of your library in another face-down pile. Look at the cards in each pile, then turn a pile of your choice face up. An opponent chooses one of those piles. Put all cards in the chosen pile into your hand and the rest into your graveyard. You lose 3 life.

Desecration Elemental

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Whenever a player casts a spell, sacrifice a creature.

Rotting Regisaur

At the beginning of your upkeep, discard a card.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Charcoal Diamond

Charcoal Diamond enters the battlefield tapped.
{T}: Add {B}.

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Jin-Gitaxias, Core Augur

Flash
At the beginning of your end step, draw seven cards.
Each opponent's maximum hand size is reduced by seven.

Feed the Swarm

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

Persist

Return target nonlegendary creature card from your graveyard to the battlefield with a -1/-1 counter on it.

Lord of the Pit

Flying, trample
At the beginning of your upkeep, sacrifice a creature other than Lord of the Pit. If you can't, Lord of the Pit deals 7 damage to you.

Doom Blade

Abyssal Persecutor

Flying, trample
You can't win the game and your opponents can't lose the game.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Painwracker Oni

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
At the beginning of your upkeep, sacrifice a creature if you don't control an Ogre.

Ringsight

The Ring tempts you. Search your library for a card that shares a color with a legendary creature you control, reveal it, put it into your hand, then shuffle.

Jon Irenicus, Shattered One

At the beginning of your end step, target opponent gains control of up to one target creature you control. Put two +1/+1 counters on it and tap it. It's goaded for the rest of the game and it gains "This creature can't be sacrificed." (It attacks each combat if able and attacks a player other than you if able.)
Whenever a creature you own but don't control attacks, you draw a card.

Yukora, the Prisoner

When Yukora, the Prisoner leaves the battlefield, sacrifice all non-Ogre creatures you control.

Changeling Outcast

Changeling (This card is every creature type.)
Changeling Outcast can't block and can't be blocked.

Thought Vessel

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Plague Reaver

At the beginning of your end step, sacrifice each other creature you control.
Discard two cards, Sacrifice Plague Reaver: Choose target opponent. Return Plague Reaver to the battlefield under that player's control at the beginning of their next upkeep.

Flesh Reaver

Whenever Flesh Reaver deals damage to a creature or opponent, Flesh Reaver deals that much damage to you.

Abhorrent Overlord

Flying
When Abhorrent Overlord enters the battlefield, create a number of 1/1 black Harpy creature tokens with flying equal to your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
At the beginning of your upkeep, sacrifice a creature.

Demonic Taskmaster

Flying
At the beginning of your upkeep, sacrifice a creature other than Demonic Taskmaster.

Counterspell

Wrong Turn

Target opponent gains control of target creature. (If an attacking or blocking creature changes controllers, it's removed from combat.)

Steel Golem

Evil Eye of Urborg

Non-Eye creatures you control can't attack.
Whenever Evil Eye of Urborg becomes blocked by a creature, destroy that creature.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Dimir Signet

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Sky Diamond

Sky Diamond enters the battlefield tapped.
{T}: Add {U}.

Phyrexian Vatmother

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
At the beginning of your upkeep, you get a poison counter.

Liege of the Pit

Flying, trample
At the beginning of your upkeep, sacrifice a creature other than Liege of the Pit. If you can't, Liege of the Pit deals 7 damage to you.
Morph {B}{B}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)