Fireslinger

{T}: This creature deals 1 damage to any target and 1 damage to you.

Flame Rift

Flame Rift deals 4 damage to each player.

Loxodon Warhammer

Equipped creature gets +3/+0 and has trample and lifelink.
Equip {3}

Barbarian Ring

{T}: Add {R}. This land deals 1 damage to you.
Threshold — {R}, {T}, Sacrifice this land: It deals 2 damage to any target. Activate only if there are seven or more cards in your graveyard.

Earthquake

Earthquake deals X damage to each creature without flying and each player.

Spear Spewer

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

Auntie Blyte, Bad Influence

Flying
Whenever a source you control deals damage to you, put that many +1/+1 counters on Auntie Blyte.
{1}{R}, {T}, Remove X +1/+1 counters from Auntie Blyte: It deals X damage to any target.

Manabarbs

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