Manabarbs

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

Pyretic Ritual

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Ruby Medallion

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

Spellshock

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

Harsh Mentor

Whenever an opponent activates an ability of an artifact, creature, or land on the battlefield, if it isn't a mana ability, Harsh Mentor deals 2 damage to that player.

Price of Glory

Whenever a player taps a land for mana, if it's not that player's turn, destroy that land.

Scytheclaw Raptor

Whenever a player casts a spell, if it's not their turn, Scytheclaw Raptor deals 4 damage to them.

Demand Answers

As an additional cost to cast this spell, sacrifice an artifact or discard a card.
Draw two cards.

Heartless Hidetsugu

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

Copper Tablet

At the beginning of each player's upkeep, Copper Tablet deals 1 damage to that player.

Furnace of Rath

If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Fanatic of Mogis

When Fanatic of Mogis enters, it deals damage to each opponent equal to your devotion to red. (Each {R} in the mana costs of permanents you control counts toward your devotion to red.)

Obsidian Fireheart

{1}{R}{R}: Put a blaze counter on target land without a blaze counter on it. For as long as that land has a blaze counter on it, it has "At the beginning of your upkeep, this land deals 1 damage to you." (The land continues to burn after Obsidian Fireheart has left the battlefield.)

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.

Stoneshaker Shaman

At the beginning of each player's end step, that player sacrifices an untapped land of their choice.

Price of Progress

Price of Progress deals damage to each player equal to twice the number of nonbasic lands that player controls.

Cemetery Gatekeeper

First strike
When Cemetery Gatekeeper enters, exile a card from a graveyard.
Whenever a player plays a land or casts a spell, if it shares a card type with the exiled card, Cemetery Gatekeeper deals 2 damage to that player.

Citadel of Pain

At the beginning of each player's end step, Citadel of Pain deals X damage to that player, where X is the number of untapped lands they control.

Zo-Zu the Punisher

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

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Fortune Thief

Damage that would reduce your life total to less than 1 reduces it to 1 instead.
Morph {R}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Rampaging Ferocidon

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

Faithless Salvaging

Discard a card, then draw a card.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Skullcage

At the beginning of each opponent's upkeep, Skullcage deals 2 damage to that player unless they have exactly three or exactly four cards in hand.

Sun Droplet

Whenever you're dealt damage, put that many charge counters on Sun Droplet.
At the beginning of each upkeep, you may remove a charge counter from Sun Droplet. If you do, you gain 1 life.

Silent Arbiter

No more than one creature can attack each combat.
No more than one creature can block each combat.

Mechanized Warfare

If a red or artifact source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 1 instead.

Magus of the Moon

Isolation Cell

Whenever an opponent casts a creature spell, that player loses 2 life unless they pay {2}.

Furnace Punisher

Menace
At the beginning of each player's upkeep, Furnace Punisher deals 2 damage to that player unless they control two or more basic lands.

Roiling Vortex

At the beginning of each player's upkeep, Roiling Vortex deals 1 damage to them.
Whenever a player casts a spell, if no mana was spent to cast that spell, Roiling Vortex deals 5 damage to that player.
{R}: Your opponents can't gain life this turn.

Iron Myr

Desperate Ritual

Add {R}{R}{R}.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

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.

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.