Ankh of Mishra

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

Aether Sting

Whenever an opponent casts a creature spell, Aether Sting deals 1 damage to that player.

Shock

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Chimeric Idol

{0}: Tap all lands you control. Chimeric Idol becomes a 3/3 Turtle artifact creature until end of turn.

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.

Guttersnipe

Whenever you cast an instant or sorcery spell, Guttersnipe deals 2 damage to each opponent.

Lava Blister

Destroy target nonbasic land unless its controller has Lava Blister deal 6 damage to them.

Coruscation Mage

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Mountain

Ensnaring Bridge

Creatures with power greater than the number of cards in your hand can't attack.

Kyren Sniper

At the beginning of your upkeep, you may have Kyren Sniper deal 1 damage to target player or planeswalker.

Well of Life

At the beginning of your end step, if you control no untapped lands, you gain 2 life.

Manabarbs

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