Death Pits of Rath

Whenever a creature is dealt damage, destroy it. It can't be regenerated.

Magewright's Stone

{1}, {T}: Untap target creature that has an activated ability with {T} in its cost.

Harvester of Souls

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever another nontoken creature dies, you may draw a card.

Mari, the Killing Quill

Whenever a creature an opponent controls dies, exile it with a hit counter on it.
Assassins, Mercenaries, and Rogues you control have deathtouch and "Whenever this creature deals combat damage to a player, you may remove a hit counter from a card that player owns in exile. If you do, draw a card and create two Treasure tokens."

Blood Cultist

{T}: Blood Cultist deals 1 damage to target creature.
Whenever a creature dealt damage by Blood Cultist this turn dies, put a +1/+1 counter on Blood Cultist.

Ruinous Ultimatum

Destroy all nonland permanents your opponents control.

Vorpal Sword

Equipped creature gets +2/+0 and has deathtouch.
{5}{B}{B}{B}: Until end of turn, Vorpal Sword gains "Whenever equipped creature deals combat damage to a player, that player loses the game."
Equip {B}{B}

Royal Assassin

Shriveling Rot

Choose one —
• Until end of turn, whenever a creature is dealt damage, destroy it.
• Until end of turn, whenever a creature dies, that creature's controller loses life equal to its toughness.
Entwine {2}{B} (Choose both if you pay the entwine cost.)

Minthara, Merciless Soul

Minthara has ward {X}, where X is the number of experience counters you have.
At the beginning of your end step, if a permanent you controlled left the battlefield this turn, you get an experience counter.
Creatures you control get +1/+0 for each experience counter you have.

Onyx Mage

{1}{B}: Target creature you control gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Reconnaissance

{0}: Remove target attacking creature you control from combat and untap it. (If you activate during end of combat, the creature will untap after it deals combat damage.)

Patriar's Seal

{T}: Add one mana of any color.
{1}, {T}: Untap target legendary creature you control.

Thornbite Staff

Equipped creature has "{2}, {T}: This creature deals 1 damage to any target" and "Whenever a creature dies, untap this creature."
Whenever a Shaman creature enters, you may attach Thornbite Staff to it.
Equip {4}

Gorgon's Head

Equipped creature has deathtouch.
Equip {2}

Humble Defector

{T}: Draw two cards. Target opponent gains control of Humble Defector. Activate only during your turn.

Goblin Sharpshooter

Goblin Sharpshooter doesn't untap during your untap step.
Whenever a creature dies, untap Goblin Sharpshooter.
{T}: Goblin Sharpshooter deals 1 damage to any target.

Retreat to Hagra

Landfall — Whenever a land you control enters, choose one —
• Target creature gets +1/+0 and gains deathtouch until end of turn.
• Each opponent loses 1 life and you gain 1 life.

Vulshok Sorcerer

Haste
{T}: Vulshok Sorcerer deals 1 damage to any target.

Neko-Te

Whenever equipped creature deals damage to a creature, tap that creature. That creature doesn't untap during its controller's untap step for as long as Neko-Te remains on the battlefield.
Whenever equipped creature deals damage to a player, that player loses 1 life.
Equip {2}

Torbran, Thane of Red Fell

If a red source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.

Thousand-Year Elixir

You may activate abilities of creatures you control as though those creatures had haste.
{1}, {T}: Untap target creature.

Kelsien, the Plague

Vigilance, haste
Kelsien, the Plague gets +1/+1 for each experience counter you have.
{T}: Kelsien deals 1 damage to target creature you don't control. When that creature dies this turn, you get an experience counter.

Chandra's Ignition

Target creature you control deals damage equal to its power to each other creature and each opponent.