Plague Spitter

At the beginning of your upkeep, this creature deals 1 damage to each creature and each player.
When this creature dies, it deals 1 damage to each creature and each player.

Vent Sentinel

Defender
{1}{R}, {T}: This creature deals damage to target player or planeswalker equal to the number of creatures you control with defender.

Warmonger

{2}: This creature deals 1 damage to each creature without flying and each player. Any player may activate this ability.

Witty Roastmaster

Alliance — Whenever another creature you control enters, this creature deals 1 damage to each opponent.

Ob Nixilis, the Adversary

Casualty X. The copy isn't legendary and has starting loyalty X. (As you cast this spell, you may sacrifice a creature with power X. When you do, copy this spell. The copy becomes a token.)
+1: Each opponent loses 2 life unless they discard a card. If you control a Demon or Devil, you gain 2 life.
−2: Create a 1/1 red Devil creature token with "When this token dies, it deals 1 damage to any target."
−7: Target player draws seven cards and loses 7 life.

Oni-Cult Anvil

Whenever one or more artifacts you control leave the battlefield during your turn, create a 1/1 colorless Construct artifact creature token. This ability triggers only once each turn.
{T}, Sacrifice an artifact: This artifact deals 1 damage to each opponent. You gain 1 life.

Crypt Rats

{X}: This creature deals X damage to each creature and each player. Spend only black mana on X.

Volcanic Spray

Volcanic Spray deals 1 damage to each creature without flying and each player.
Flashback {1}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Dry Spell

Dry Spell deals 1 damage to each creature and each player.

Relic Robber

Haste
Whenever this creature deals combat damage to a player, that player creates a 0/1 colorless Goblin Construct artifact creature token with "This token can't block" and "At the beginning of your upkeep, this token deals 1 damage to you."

Dreadhound

When this creature enters, mill three cards. (Put the top three cards of your library into your graveyard.)
Whenever a creature dies or a creature card is put into a graveyard from a library, each opponent loses 1 life.

Withering Wisps

At the beginning of the end step, if no creatures are on the battlefield, sacrifice this enchantment.
{B}: This enchantment deals 1 damage to each creature and each player. Activate no more times each turn than the number of snow Swamps you control.

Thermo-Alchemist

Defender
{T}: This creature deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap this creature.

Urborg Stalker

At the beginning of each player's upkeep, if that player controls a nonblack, nonland permanent, this creature deals 1 damage to that player.

Necrotic Ooze

As long as this creature is on the battlefield, it has all activated abilities of all creature cards in all graveyards.

Rakdos Charm

Choose one —
• Exile target player's graveyard.
• Destroy target artifact.
• Each creature deals 1 damage to its controller.

Whispering Snitch

Whenever you surveil for the first time each turn, this creature deals 1 damage to each opponent and you gain 1 life.