Spirit Loop

Enchant creature you control
Whenever enchanted creature deals damage, you gain that much life.
When Spirit Loop is put into a graveyard from the battlefield, return Spirit Loop to its owner's hand.

Spirit Link

Enchant creature (Target a creature as you cast this. This card enters the battlefield attached to that creature.)
Whenever enchanted creature deals damage, you gain that much life.

Elder Mastery

Enchant creature
Enchanted creature gets +3/+3 and has flying.
Whenever enchanted creature deals damage to a player, that player discards two cards.

Armadillo Cloak

Enchant creature
Enchanted creature gets +2/+2 and has trample.
Whenever enchanted creature deals damage, you gain that much life.

Vampiric Link

Enchant creature
Whenever enchanted creature deals damage, you gain that much life.

Sigil of Sleep

Enchant creature
Whenever enchanted creature deals damage to a player, return target creature that player controls to its owner's hand.

Helm of the Ghastlord

Enchant creature
As long as enchanted creature is blue, it gets +1/+1 and has "Whenever this creature deals damage to an opponent, draw a card."
As long as enchanted creature is black, it gets +1/+1 and has "Whenever this creature deals damage to an opponent, that player discards a card."

Curiosity

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Burning Anger

Enchant creature
Enchanted creature has "{T}: This creature deals damage equal to its power to any target."

Keen Sense

Ophidian Eye

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Soul Link

Enchant creature
Whenever enchanted creature deals damage, you gain that much life.
Whenever enchanted creature is dealt damage, you gain that much life.