Pestilence

At the beginning of the end step, if no creatures are on the battlefield, sacrifice Pestilence.
{B}: Pestilence deals 1 damage to each creature and each player.

Smallpox

Each player loses 1 life, discards a card, sacrifices a creature, then sacrifices a land.

Mages' Contest

You and target spell's controller bid life. You start the bidding with a bid of 1. In turn order, each player may top the high bid. The bidding ends if the high bid stands. The high bidder loses life equal to the high bid. If you win the bidding, counter that spell.

Collective Brutality

Escalate—Discard a card. (Pay this cost for each mode chosen beyond the first.)
Choose one or more —
• Target opponent reveals their hand. You choose an instant or sorcery card from it. That player discards that card.
• Target creature gets -2/-2 until end of turn.
• Target opponent loses 2 life and you gain 2 life.

Archfiend of Despair

Flying
Your opponents can't gain life.
At the beginning of each end step, each opponent loses life equal to the life that player lost this turn. (Damage causes loss of life.)

Havoc Festival

Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up.

Sign in Blood

Target player draws two cards and loses 2 life.

Kaervek's Torch

As long as Kaervek's Torch is on the stack, spells that target it cost {2} more to cast.
Kaervek's Torch deals X damage to any target.

Fell Specter

Flying
When Fell Specter enters, target opponent discards a card.
Whenever an opponent discards a card, that player loses 2 life.

Stronghold Rats

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Stronghold Rats deals combat damage to a player, each player discards a card.

Heartless Hidetsugu

{T}: Heartless Hidetsugu deals damage to each player equal to half that player's life total, rounded down.

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Crypt Ripper

Haste
{B}: Crypt Ripper gets +1/+1 until end of turn.

Zo-Zu the Punisher

Whenever a land enters, Zo-Zu the Punisher deals 2 damage to that land's controller.

Duskwielder

Boast — {1}: Target opponent loses 1 life and you gain 1 life. (Activate only if this creature attacked this turn and only once each turn.)

Sarevok, Deathbringer

At the beginning of each player's end step, if no permanents left the battlefield this turn, that player loses X life, where X is Sarevok's power.
Choose a Background (You can have a Background as a second commander.)

Pyrohemia

At the beginning of the end step, if no creatures are on the battlefield, sacrifice Pyrohemia.
{R}: Pyrohemia deals 1 damage to each creature and each player.

Quest for the Nihil Stone

Whenever an opponent discards a card, you may put a quest counter on Quest for the Nihil Stone.
At the beginning of each opponent's upkeep, if that player has no cards in hand and Quest for the Nihil Stone has two or more quest counters on it, you may have that player lose 5 life.

Nettling Curse

Enchant creature
Whenever enchanted creature attacks or blocks, its controller loses 3 life.
{1}{R}: Enchanted creature attacks this turn if able.

Ankh of Mishra

Whenever a land enters, Ankh of Mishra deals 2 damage to that land's controller.

Rug of Smothering

Flying
Whenever a player casts a spell, they lose 1 life for each spell they've cast this turn.

Pyrostatic Pillar

Whenever a player casts a spell with mana value 3 or less, Pyrostatic Pillar deals 2 damage to that player.

Arrogant Outlaw

When Arrogant Outlaw enters, if an opponent lost life this turn, each opponent loses 2 life and you gain 2 life.

Leyline of Punishment

If Leyline of Punishment is in your opening hand, you may begin the game with it on the battlefield.
Players can't gain life.
Damage can't be prevented.

Damnation

Destroy all creatures. They can't be regenerated.

Sulfuric Vortex

At the beginning of each player's upkeep, Sulfuric Vortex deals 2 damage to that player.
If a player would gain life, that player gains no life instead.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Impatience

At the beginning of each player's end step, if that player didn't cast a spell this turn, Impatience deals 2 damage to that player.

Wound Reflection

At the beginning of each end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)

Rain of Embers

Rain of Embers deals 1 damage to each creature and each player.

Bottomless Pit

At the beginning of each player's upkeep, that player discards a card at random.

Jet Medallion

Black spells you cast cost {1} less to cast.

Boompile

{T}: Flip a coin. If you win the flip, destroy all nonland permanents.

Rain of Gore

If a spell or ability would cause its controller to gain life, that player loses that much life instead.

Rotting Rats

When Rotting Rats enters, each player discards a card.
Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Syphon Mind

Each other player discards a card. You draw a card for each card discarded this way.

Mindslicer

When Mindslicer dies, each player discards their hand.

Sol Ring

Stunning Reversal

The next time you would lose the game this turn, instead draw seven cards and your life total becomes 1.
Exile Stunning Reversal.

Bad Deal

You draw two cards and each opponent discards two cards. Each player loses 2 life.

Impending Disaster

At the beginning of your upkeep, if there are seven or more lands on the battlefield, sacrifice Impending Disaster and destroy all lands.

Spellshock

Whenever a player casts a spell, Spellshock deals 2 damage to that player.

Caged Zombie

{1}{B}, {T}: Each opponent loses 2 life. Activate only if a creature died this turn.

Everlasting Torment

Players can't gain life.
Damage can't be prevented.
All damage is dealt as though its source had wither. (A source with wither deals damage to creatures in the form of -1/-1 counters.)

Nevinyrral's Disk

Nevinyrral's Disk enters tapped.
{1}, {T}: Destroy all artifacts, creatures, and enchantments.

Coalhauler Swine

Whenever Coalhauler Swine is dealt damage, it deals that much damage to each player.

Manabarbs

Whenever a player taps a land for mana, Manabarbs deals 1 damage to that player.

Rampaging Ferocidon

Menace
Players can't gain life.
Whenever another creature enters, Rampaging Ferocidon deals 1 damage to that creature's controller.

Rakdos, Lord of Riots

You can't cast this spell unless an opponent lost life this turn.
Flying, trample
Creature spells you cast cost {1} less to cast for each 1 life your opponents have lost this turn.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

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.)

Flame Rift

Flame Rift deals 4 damage to each player.

Forsaken Wastes

Players can't gain life.
At the beginning of each player's upkeep, that player loses 1 life.
Whenever Forsaken Wastes becomes the target of a spell, that spell's controller loses 5 life.

Liliana's Caress

Whenever an opponent discards a card, that player loses 2 life.

Jokulhaups

Destroy all artifacts, creatures, and lands. They can't be regenerated.

Charcoal Diamond

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

Thought Vessel

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

Skullcrack

Players can't gain life this turn. Damage can't be prevented this turn. Skullcrack deals 3 damage to target player or planeswalker.