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.

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.

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.

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.

Shadowborn Demon

Flying
When Shadowborn Demon enters, destroy target non-Demon creature.
At the beginning of your upkeep, if there are fewer than six creature cards in your graveyard, sacrifice a creature.

Priest of the Blood Rite

When Priest of the Blood Rite enters, create a 5/5 black Demon creature token with flying.
At the beginning of your upkeep, you lose 2 life.

Apocalypse Demon

Flying
Apocalypse Demon's power and toughness are each equal to the number of cards in your graveyard.
At the beginning of your upkeep, tap Apocalypse Demon unless you sacrifice another creature.

Evil Eye of Orms-by-Gore

Non-Eye creatures you control can't attack.
Evil Eye of Orms-by-Gore can't be blocked except by Walls.

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.

Serendib Efreet

Flying
At the beginning of your upkeep, Serendib Efreet deals 1 damage to you.

Benthic Djinn

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
At the beginning of your upkeep, you lose 2 life.

Pitiless Horde

At the beginning of your upkeep, you lose 2 life.
Dash {2}{B}{B} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Rotting Regisaur

At the beginning of your upkeep, discard a card.

Archdemon of Greed

Flying, trample
At the beginning of your upkeep, sacrifice a Human. If you can't, tap Archdemon of Greed and it deals 9 damage to you.

Ravenous Demon

Sacrifice a Human: Transform Ravenous Demon. Activate only as a sorcery.

Ravenous Demon // Archdemon of Greed

Bloodcurdler

Flying
At the beginning of your upkeep, mill a card.
Threshold — As long as seven or more cards are in your graveyard, Bloodcurdler gets +1/+1 and has "At the beginning of your end step, exile two cards from your graveyard."

Herald of Torment

Bestow {3}{B}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying
At the beginning of your upkeep, you lose 1 life.
Enchanted creature gets +3/+3 and has flying.

Demonic Hordes

{T}: Destroy target land.
At the beginning of your upkeep, unless you pay {B}{B}{B}, tap Demonic Hordes and sacrifice a land of an opponent's choice.

Aku Djinn

Trample
At the beginning of your upkeep, put a +1/+1 counter on each creature each opponent controls.

Abyssal Persecutor

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

Esperzoa

Flying
At the beginning of your upkeep, return an artifact you control to its owner's hand.

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.

Master of the Feast

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

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.

Demonic Taskmaster

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

Keen Duelist

At the beginning of your upkeep, you and target opponent each reveal the top card of your library. You each lose life equal to the mana value of the card revealed by the other player. You each put the card you revealed into your hand.

Minion of Tevesh Szat

At the beginning of your upkeep, Minion of Tevesh Szat deals 2 damage to you unless you pay {B}{B}.
{T}: Target creature gets +3/-2 until end of turn.

Grinning Demon

At the beginning of your upkeep, you lose 2 life.
Morph {2}{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.)

Scourge of Numai

At the beginning of your upkeep, you lose 2 life if you don't control an Ogre.

Taniwha

Trample
Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)
At the beginning of your upkeep, all lands you control phase out. (They phase in before you untap during your next untap step.)

Hellcarver Demon

Flying
Whenever Hellcarver Demon deals combat damage to a player, sacrifice all other permanents you control and discard your hand. Exile the top six cards of your library. You may cast any number of spells from among cards exiled this way without paying their mana costs.

Treacherous Pit-Dweller

When Treacherous Pit-Dweller enters from a graveyard, target opponent gains control of it.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Vampire Lacerator

At the beginning of your upkeep, you lose 1 life unless an opponent has 10 or less life.

Archfiend of the Dross

Flying
Archfiend of the Dross enters 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.

Moroii

Flying
At the beginning of your upkeep, you lose 1 life.

Mindwrack Demon

Flying, trample
When Mindwrack Demon enters, mill four cards.
Delirium — At the beginning of your upkeep, you lose 4 life unless there are four or more card types among cards in your graveyard.

Gutwrencher Oni

Trample
At the beginning of your upkeep, discard a card if you don't control an Ogre.

Minion of Leshrac

Protection from black
At the beginning of your upkeep, Minion of Leshrac deals 5 damage to you unless you sacrifice a creature other than Minion of Leshrac. If Minion of Leshrac deals damage to you this way, tap it.
{T}: Destroy target creature or land.

Abhorrent Overlord

Flying
When Abhorrent Overlord enters, 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.

Reaver Drone

Devoid (This card has no color.)
At the beginning of your upkeep, you lose 1 life unless you control another colorless creature.

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.

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.

Xathrid Demon

Flying, trample
At the beginning of your upkeep, sacrifice a creature other than Xathrid Demon, then each opponent loses life equal to the sacrificed creature's power. If you can't sacrifice a creature, tap Xathrid Demon and you lose 7 life.