Arcane Teachings

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature gets +2/+2 and has "{T}: This creature deals 1 damage to any target."

Barbed Field

Enchant land
Enchanted land has "{T}: This land deals 1 damage to any target."

Ghyrson Starn, Kelermorph

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Three Autostubs — Whenever another source you control deals exactly 1 damage to a permanent or player, Ghyrson Starn deals 2 damage to that permanent or player.

Aggravate

Aggravate deals 1 damage to each creature target player controls. Each creature dealt damage this way attacks this turn if able.

Akoum Hellkite

Flying
Landfall — Whenever a land you control enters, this creature deals 1 damage to any target. If that land is a Mountain, this creature deals 2 damage instead.

Barrage of Expendables

{R}, Sacrifice a creature: This enchantment deals 1 damage to any target.

Aether Sting

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