Ancestral Mask

Enchant creature
Enchanted creature gets +2/+2 for each other enchantment on the battlefield.

Boiling Seas

Blessing of the Nephilim

Enchant creature
Enchanted creature gets +1/+1 for each of its colors.

Boil

Boar Umbra

Enchant creature
Enchanted creature gets +3/+3.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Armadillo Cloak

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

Armor of Thorns

You may cast Armor of Thorns as though it had flash. If you cast it any time a sorcery couldn't have been cast, the controller of the permanent it becomes sacrifices it at the beginning of the next cleanup step.
Enchant nonblack creature
Enchanted creature gets +2/+2.

Angelic Gift

Enchant creature
When Angelic Gift enters the battlefield, draw a card.
Enchanted creature has flying.

Audacity

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When Audacity is put into a graveyard from the battlefield, draw a card.

Aether Web

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+1, has reach, and can block creatures with shadow as though they didn't have shadow. (Creatures with reach can block creatures with flying.)

Uril, the Miststalker

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Uril, the Miststalker gets +2/+2 for each Aura attached to it.

All That Glitters

Enchant creature
Enchanted creature gets +1/+1 for each artifact and/or enchantment you control.

Akki War Paint

Enchant artifact or creature
As long as enchanted permanent is a creature, it gets +2/+1.

Arachnoform

Enchant creature
Enchanted creature gets +2/+2, has reach, and is every creature type.