Eidolon of Countless Battles

Bestow {2}{W}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Eidolon of Countless Battles and enchanted creature each get +1/+1 for each creature you control and +1/+1 for each Aura you control.

Harvestguard Alseids

Constellation — Whenever Harvestguard Alseids or another enchantment you control enters, prevent all damage that would be dealt to target creature this turn.

Auramancer

When Auramancer enters, you may return target enchantment card from your graveyard to your hand.

Songbirds' Blessing

Enchant creature
Whenever enchanted creature attacks, reveal cards from the top of your library until you reveal an Aura card. You may put that card onto the battlefield. If you don't, put it into your hand. Put the rest on the bottom of your library in a random order.

Tiana, Ship's Caretaker

Flying, first strike
Whenever an Aura or Equipment you control is put into a graveyard from the battlefield, you may return that card to its owner's hand at the beginning of the next end step.

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.

Eidolon of Blossoms

Constellation — Whenever Eidolon of Blossoms or another enchantment you control enters, draw a card.

Inviolability

Enchant creature
Prevent all damage that would be dealt to enchanted creature.

Daybreak Coronet

Enchant creature with another Aura attached to it
Enchanted creature gets +3/+3 and has first strike, vigilance, and lifelink. (Damage dealt by the creature also causes its controller to gain that much life.)

Bear Umbra

Enchant creature
Enchanted creature gets +2/+2 and has "Whenever this creature attacks, untap all lands you control."
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Spectra Ward

Enchant creature
Enchanted creature gets +2/+2 and has protection from each color. This effect doesn't remove Auras. (It can't be blocked, targeted, or dealt damage by anything that's white, blue, black, red, or green.)

Open the Gates

Search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

Umbra Mystic

Auras attached to permanents you control have umbra armor. (If an enchanted permanent you control would be destroyed, instead remove all damage from it and destroy an Aura attached to it.)

Colossification

Enchant creature
When Colossification enters, tap enchanted creature.
Enchanted creature gets +20/+20.

Mountain

Setessan Champion

Constellation — Whenever an enchantment you control enters, put a +1/+1 counter on Setessan Champion and draw a card.

Armadillo Cloak

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

Open the Armory

Search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Plains

Siona, Captain of the Pyleas

When Siona, Captain of the Pyleas enters, look at the top seven cards of your library. You may reveal an Aura card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Whenever an Aura you control becomes attached to a creature you control, create a 1/1 white Human Soldier creature token.

Rishkar's Expertise

Draw cards equal to the greatest power among creatures you control.
You may cast a spell with mana value 5 or less from your hand without paying its mana cost.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Dawnhart Geist

Whenever you cast an enchantment spell, you gain 2 life.

On Serra's Wings

Enchant creature
Enchanted creature is legendary, gets +1/+1, and has flying, vigilance, and lifelink.

One with Nature

Enchant creature
Whenever enchanted creature deals combat damage to a player, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Boon of the Spirit Realm

Constellation — Whenever Boon of the Spirit Realm or another enchantment you control enters, put a blessing counter on Boon of the Spirit Realm.
Creatures you control get +1/+1 for each blessing counter on Boon of the Spirit Realm.

Celestial Ancient

Flying
Whenever you cast an enchantment spell, put a +1/+1 counter on each creature you control.

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.)

Karametra's Favor

Enchant creature
When Karametra's Favor enters, draw a card.
Enchanted creature has "{T}: Add one mana of any color."

Forest

Empyrial Armor

Enchant creature
Enchanted creature gets +1/+1 for each card in your hand.

Hyena Umbra

Enchant creature
Enchanted creature gets +1/+1 and has first strike.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Nessian Wanderer

Constellation — Whenever an enchantment you control enters, look at the top three cards of your library. You may reveal a land card from among them and put that card into your hand. Put the rest on the bottom of your library in a random order.

Favored of Iroas

Constellation — Whenever an enchantment you control enters, Favored of Iroas gains double strike until end of turn. (It deals both first-strike and regular combat damage.)

Three Dreams

Search your library for up to three Aura cards with different names, reveal them, put them into your hand, then shuffle.

Eidolon of Inspiration

At the beginning of combat on your turn, target creature you control gets +2/+0 until end of turn.

Krosan Grip

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Destroy target artifact or enchantment.

Kor Spiritdancer

Kor Spiritdancer gets +2/+2 for each Aura attached to it.
Whenever you cast an Aura spell, you may draw a card.

Sage's Reverie

Enchant creature
When Sage's Reverie enters, draw a card for each Aura you control that's attached to a creature.
Enchanted creature gets +1/+1 for each Aura you control that's attached to a creature.

Ancestral Mask

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

Spirit Mantle

Enchant creature
Enchanted creature gets +1/+1 and has protection from creatures.

Champion of the Flame

Trample
Champion of the Flame gets +2/+2 for each Aura and Equipment attached to it.

Oakheart Dryads

Constellation — Whenever Oakheart Dryads or another enchantment you control enters, target creature gets +1/+1 until end of turn.

Pious Wayfarer

Constellation — Whenever an enchantment you control enters, target creature gets +1/+1 until end of turn.

Mammoth Umbra

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

Ajani's Chosen

Whenever an enchantment you control enters, create a 2/2 white Cat creature token. If that enchantment is an Aura, you may attach it to the token.

Sram, Senior Edificer

Whenever you cast an Aura, Equipment, or Vehicle spell, draw a card.

Rancor

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When Rancor is put into a graveyard from the battlefield, return Rancor to its owner's hand.

Chishiro, the Shattered Blade

Whenever an Aura or Equipment you control enters, create a 2/2 red Spirit creature token with menace.
At the beginning of your end step, put a +1/+1 counter on each modified creature you control. (Equipment, Auras you control, and counters are modifications.)

Goldenhide Ox

Constellation — Whenever Goldenhide Ox or another enchantment you control enters, target creature must be blocked this turn if able.

Faith Unbroken

Enchant creature you control
When Faith Unbroken enters, exile target creature an opponent controls until Faith Unbroken leaves the battlefield.
Enchanted creature gets +2/+2.

All That Glitters

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

Unquestioned Authority

Enchant creature
When Unquestioned Authority enters, draw a card.
Enchanted creature has protection from creatures.

Nature's Claim

Destroy target artifact or enchantment. Its controller gains 4 life.

Madcap Skills

Enchant creature
Enchanted creature gets +3/+0 and has menace.

Ethereal Armor

Enchant creature
Enchanted creature gets +1/+1 for each enchantment you control and has first strike.

Nexus Wardens

Reach
Constellation — Whenever an enchantment you control enters, you gain 2 life.

Life's Legacy

As an additional cost to cast this spell, sacrifice a creature.
Draw cards equal to the sacrificed creature's power.