Ebon Drake

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

Flesh Reaver

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

Slip Out the Back

Put a +1/+1 counter on target creature. It phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

Feign Death

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Hunted Phantasm

Hunted Phantasm can't be blocked.
When Hunted Phantasm enters, target opponent creates five 1/1 red Goblin creature tokens.

Reins of Power

Untap all creatures you control and all creatures target opponent controls. You and that opponent each gain control of all creatures the other controls until end of turn. Those creatures gain haste until end of turn.

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.

Demonic Taskmaster

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

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.)

Switcheroo

Exchange control of two target creatures.

Bellowing Fiend

Flying
Whenever Bellowing Fiend deals damage to a creature, Bellowing Fiend deals 3 damage to that creature's controller and 3 damage to you.

Ebonblade Reaper

Whenever Ebonblade Reaper attacks, you lose half your life, rounded up.
Whenever Ebonblade Reaper deals combat damage to a player, that player loses half their life, rounded up.
Morph {3}{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.)

Phyrexian Soulgorger

Cumulative upkeep—Sacrifice a creature. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Calculating Lich

Menace
Whenever a creature attacks one of your opponents, that player loses 1 life.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

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.

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.

Wrong Turn

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

Clackbridge Troll

Trample, haste
When Clackbridge Troll enters, target opponent creates three 0/1 white Goat creature tokens.
At the beginning of combat on your turn, any opponent may sacrifice a creature of their choice. If a player does, tap Clackbridge Troll, you gain 3 life, and you draw a card.

Drinker of Sorrow

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

Hasran Ogress

Whenever Hasran Ogress attacks, it deals 3 damage to you unless you pay {2}.

Sleeper Agent

When Sleeper Agent enters, target opponent gains control of it.
At the beginning of your upkeep, Sleeper Agent deals 2 damage to you.

Steel Golem

Master of the Feast

Flying
At the beginning of your upkeep, each opponent draws a card.

Rotting Regisaur

At the beginning of your upkeep, discard a card.

Akroan Horse

Defender
When Akroan Horse enters, an opponent gains control of it.
At the beginning of your upkeep, each opponent creates a 1/1 white Soldier creature token.

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.

Wretched Anurid

Whenever another creature enters, you lose 1 life.

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.

Abyssal Persecutor

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

Phyrexian Negator

Trample
Whenever Phyrexian Negator is dealt damage, sacrifice that many permanents.