Valakut Exploration

Landfall — Whenever a land you control enters, exile the top card of your library. You may play that card for as long as it remains exiled.
At the beginning of your end step, if there are cards exiled with this enchantment, put them into their owner's graveyard, then this enchantment deals that much damage to each opponent.

Ash Zealot

First strike, haste
Whenever a player casts a spell from a graveyard, this creature deals 3 damage to that player.

Tunnel Ignus

Whenever a land enters under an opponent's control, if that player had another land enter the battlefield under their control this turn, this creature deals 3 damage to that player.

Rivalry

At the beginning of each player's upkeep, if that player controls more lands than each other player, this enchantment deals 2 damage to them.

Dismissive Pyromancer

{R}, {T}, Discard a card: Draw a card.
{2}{R}, {T}, Sacrifice this creature: It deals 4 damage to target creature.

Spear Spewer

Defender
{T}: This creature deals 1 damage to each player.

Immolation Shaman

Whenever an opponent activates an ability of an artifact, creature, or land that isn't a mana ability, this creature deals 1 damage to that player.
{3}{R}{R}: This creature gets +3/+3 and gains menace until end of turn.

Scalding Tongs

At the beginning of your upkeep, if you have three or fewer cards in hand, this artifact deals 1 damage to target opponent or planeswalker.

Harsh Mentor

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

Scab-Clan Berserker

Haste
Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever an opponent casts a noncreature spell, if this creature is renowned, this creature deals 2 damage to that player.

Oath of Mages

At the beginning of each player's upkeep, that player chooses target player who has more life than they do and is their opponent. The first player may have this enchantment deal 1 damage to the second player.

Psychogenic Probe

Whenever a spell or ability causes a player to shuffle their library, this artifact deals 2 damage to that player.

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.

Tectonic Reformation

Each land card in your hand has cycling {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Invader Parasite

Imprint — When this creature enters, exile target land.
Whenever a land an opponent controls with the same name as the exiled card enters, this creature deals 2 damage to that player.

Gibbering Fiend

When this creature enters, it deals 1 damage to each opponent.
Delirium — At the beginning of each opponent's upkeep, if there are four or more card types among cards in your graveyard, this creature deals 1 damage to that player.

Tibalt, Rakish Instigator

Your opponents can't gain life.
−2: Create a 1/1 red Devil creature token with "When this token dies, it deals 1 damage to any target."

Fanatic of Mogis

When this creature 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.)

Sun Droplet

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

Viseling

At the beginning of each opponent's upkeep, this creature deals X damage to that player, where X is the number of cards in their hand minus 4.

Zo-Zu the Punisher

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

Manabarbs

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

Grim Lavamancer

{R}, {T}, Exile two cards from your graveyard: This creature deals 2 damage to any target.

Roiling Vortex

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

Skullcage

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

Aether Sting

Whenever an opponent casts a creature spell, this enchantment deals 1 damage to that player.

Leyline of Combustion

If this card is in your opening hand, you may begin the game with it on the battlefield.
Whenever you and/or at least one permanent you control becomes the target of a spell or ability an opponent controls, this enchantment deals 2 damage to that player.

Burning Earth

Whenever a player taps a nonbasic land for mana, this enchantment deals 1 damage to that player.