Maybe

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.

Have

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.)

Helm of the Gods

Equipped creature gets +1/+1 for each enchantment you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Thran Power Suit

Equipped creature gets +1/+1 for each Aura and Equipment attached to it and has ward {2}. (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Mesa Enchantress

Whenever you cast an enchantment spell, you may draw a card.

Roadside Reliquary

{T}: Add {C}.
{2}, {T}, Sacrifice Roadside Reliquary: Draw a card if you control an artifact. Draw a card if you control an enchantment.

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Retether

Return each Aura card from your graveyard to the battlefield. Only creatures can be enchanted this way. (Aura cards that can't enchant a creature on the battlefield remain in your graveyard.)

Grand Abolisher

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.

Seal of Cleansing

Sacrifice Seal of Cleansing: Destroy target artifact or enchantment.

Hall of Heliod's Generosity

{T}: Add {C}.
{1}{W}, {T}: Put target enchantment card from your graveyard on top of your library.

Xenk, Paladin Unbroken

Double strike
Auras you control have exalted. (Whenever a creature you control attacks alone, it gets +1/+1 until end of turn for each instance of exalted among permanents you control.)

Recruitment Officer

{3}{W}: Look at the top four cards of your library. You may reveal a creature card with mana value 3 or less from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Land Tax

At the beginning of your upkeep, if an opponent controls more lands than you, you may search your library for up to three basic land cards, reveal them, put them into your hand, then shuffle.

Ironclad Slayer

When Ironclad Slayer enters, you may return target Aura or Equipment card from your graveyard to your hand.

Eland Umbra

Enchant creature
Enchanted creature gets +0/+4.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Loyal Warhound

Vigilance
When Loyal Warhound enters, if an opponent controls more lands than you, search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Sphere of Safety

Creatures can't attack you or planeswalkers you control unless their controller pays {X} for each of those creatures, where X is the number of enchantments you control.

Robe of Stars

Equipped creature gets +0/+3.
Astral Projection — {1}{W}: Equipped creature phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)
Equip {1}

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.)

Archon of the Wild Rose

Flying
Other creatures you control that are enchanted by Auras you control have base power and toughness 4/4 and have flying.

All That Glitters

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

Spirited Companion

When Spirited Companion enters, draw a card.

Blacksmith's Skill

Target permanent gains hexproof and indestructible until end of turn. If it's an artifact creature, it gets +2/+2 until end of turn.

Minimus Containment

Enchant nonland permanent
Enchanted permanent is a Treasure artifact with "{T}, Sacrifice this artifact: Add one mana of any color," and it loses all other abilities. (If it was a creature, it's no longer a creature.)

Cleansing Nova

Choose one —
• Destroy all creatures.
• Destroy all artifacts and enchantments.

Katilda's Rising Dawn

Enchant creature
Enchanted creature has flying, lifelink, and protection from Vampires, and it gets +X/+X, where X is the number of permanents you control that are Spirits and/or enchantments.
If Katilda's Rising Dawn would be put into a graveyard from anywhere, exile it instead.

Katilda, Dawnhart Martyr

Flying, lifelink, protection from Vampires
Katilda, Dawnhart Martyr's power and toughness are each equal to the number of permanents you control that are Spirits and/or enchantments.
Disturb {3}{W}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Katilda, Dawnhart Martyr // Katilda's Rising Dawn

Rune-Tail's Essence

Prevent all damage that would be dealt to creatures you control.

Rune-Tail, Kitsune Ascendant

When you have 30 or more life, flip Rune-Tail, Kitsune Ascendant.

Rune-Tail, Kitsune Ascendant // Rune-Tail's Essence

Mistveil Plains

({T}: Add {W}.)
Mistveil Plains enters tapped.
{W}, {T}: Put target card from your graveyard on the bottom of your library. Activate only if you control two or more white permanents.

Moon-Blessed Cleric

Divine Intervention — When Moon-Blessed Cleric enters, you may search your library for an enchantment card, reveal it, then shuffle and put that card on top.

Sigil of the Empty Throne

Whenever you cast an enchantment spell, create a 4/4 white Angel creature token with flying.

Vow of Duty

Enchant creature
Enchanted creature gets +2/+2, has vigilance, and can't attack you or planeswalkers you control.

Disenchant

Sentinel's Eyes

Enchant creature
Enchanted creature gets +1/+1 and has vigilance.
Escape—{W}, Exile two other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Unquestioned Authority

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

Archon of Sun's Grace

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Pegasus creatures you control have lifelink.
Constellation — Whenever an enchantment you control enters, create a 2/2 white Pegasus creature token with flying.

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.

Ondu Spiritdancer

Whenever an enchantment you control enters, you may create a token that's a copy of it. Do this only once each turn.

Entangler

Enchant creature
Enchanted creature can block any number of creatures.

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.

Felidar Umbra

Enchant creature
Enchanted creature has lifelink.
{1}{W}: Attach Felidar Umbra to target creature you control.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Throne of Eldraine

As Throne of Eldraine enters, choose a color.
{T}: Add four mana of the chosen color. Spend this mana only to cast monocolored spells of that color.
{3}, {T}: Draw two cards. Spend only mana of the chosen color to activate this ability.

Winds of Rath

Destroy all creatures that aren't enchanted. They can't be regenerated.

Sigarda's Aid

You may cast Aura and Equipment spells as though they had flash.
Whenever an Equipment you control enters, you may attach it to target creature you control.

Mantle of the Ancients

Enchant creature you control
When Mantle of the Ancients enters, return any number of target Aura and/or Equipment cards from your graveyard to the battlefield attached to enchanted creature.
Enchanted creature gets +1/+1 for each Aura and Equipment attached to it.

Pentarch Ward

Enchant creature
As Pentarch Ward enters, choose a color.
When Pentarch Ward enters, draw a card.
Enchanted creature has protection from the chosen color. This effect doesn't remove Pentarch Ward.

Hero of Iroas

Aura spells you cast cost {1} less to cast.
Heroic — Whenever you cast a spell that targets Hero of Iroas, put a +1/+1 counter on Hero of Iroas.

Gift of Immortality

Enchant creature
When enchanted creature dies, return that card to the battlefield under its owner's control. Return Gift of Immortality to the battlefield attached to that creature at the beginning of the next end step.

Transcendent Envoy

Flying
Aura spells you cast cost {1} less to cast.

Light-Paws, Emperor's Voice

Whenever an Aura you control enters, if you cast it, you may search your library for an Aura card with mana value less than or equal to that Aura and with a different name than each Aura you control, put that card onto the battlefield attached to Light-Paws, Emperor's Voice, then shuffle.

Plains

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.)

Spirit Mantle

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

Stoneskin

Flash
Enchant creature
Enchanted creature gets +0/+10.

Mother of Runes

{T}: Target creature you control gains protection from the color of your choice until end of turn.

Danitha Capashen, Paragon

First strike, vigilance, lifelink
Aura and Equipment spells you cast cost {1} less to cast.

Burnished Hart

{3}, Sacrifice Burnished Hart: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Indestructibility

Enchant permanent
Enchanted permanent has indestructible. (Effects that say "destroy" don't destroy that permanent. A creature with indestructible can't be destroyed by damage.)

Pearl Medallion

White spells you cast cost {1} less to cast.

Armored Ascension

Enchant creature
Enchanted creature gets +1/+1 for each Plains you control and has flying.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Pariah

Enchant creature
All damage that would be dealt to you is dealt to enchanted creature instead.

Starfield Mystic

Enchantment spells you cast cost {1} less to cast.
Whenever an enchantment you control is put into a graveyard from the battlefield, put a +1/+1 counter on Starfield Mystic.

Rebuff the Wicked

Counter target spell that targets a permanent you control.

Starnheim Courser

Flying
Artifact and enchantment spells you cast cost {1} less to cast.

Timely Ward

You may cast Timely Ward as though it had flash if it targets a commander.
Enchant creature
Enchanted creature has indestructible.

Petrify

Enchant artifact or creature
Enchanted permanent can't attack or block, and its activated abilities can't be activated.

Kor Spiritdancer

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

Face of Divinity

Enchant creature
Enchanted creature gets +2/+2.
As long as another Aura is attached to enchanted creature, it has first strike and lifelink.

Ethereal Armor

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

Kor Cartographer

When Kor Cartographer enters, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Oreskos Explorer

When Oreskos Explorer enters, search your library for up to X Plains cards, where X is the number of players who control more lands than you. Reveal those cards, put them into your hand, then shuffle.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Open the Vaults

Return all artifact and enchantment cards from all graveyards to the battlefield under their owners' control. (Auras with nothing to enchant remain in graveyards.)

Gift of Estates

If an opponent controls more lands than you, search your library for up to three Plains cards, reveal them, put them into your hand, then shuffle.

Daxos, Blessed by the Sun

Daxos's toughness is equal to your devotion to white. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)
Whenever another creature you control enters or dies, you gain 1 life.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Unfinished Business

Return target creature card from your graveyard to the battlefield, then return up to two target Aura and/or Equipment cards from your graveyard to the battlefield attached to that creature. (If the Auras can't enchant that creature, they remain in your graveyard.)

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.)

Holy Avenger

Equipped creature has double strike.
Whenever equipped creature deals combat damage, you may put an Aura card from your hand onto the battlefield attached to it.
Equip {2}{W}

Stroke of Midnight

Destroy target nonland permanent. Its controller creates a 1/1 white Human creature token.

Surge of Salvation

You and permanents you control gain hexproof until end of turn. Prevent all damage that black and/or red sources would deal to creatures you control this turn.

Knight of the White Orchid

First strike
When Knight of the White Orchid enters, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield, then shuffle.

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Spirit Link

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

Silence

Your opponents can't cast spells this turn.

Angelic Gift

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

On Serra's Wings

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

Haystack

{2}, {T}: Target creature you control phases out. (Treat it and anything attached to it as though they don't exist until your next turn.)

Verge Rangers

First strike
You may look at the top card of your library any time.
As long as an opponent controls more lands than you, you may play lands from the top of your library. (You can play a land this way only if you have an available land play remaining.)

Battle Mastery

Enchant creature
Enchanted creature has double strike. (It deals both first-strike and regular combat damage.)

Triclopean Sight

Flash
Enchant creature
When Triclopean Sight enters, untap enchanted creature.
Enchanted creature gets +1/+1 and has vigilance.

Darksteel Mutation

Enchant creature
Enchanted creature is an Insect artifact creature with base power and toughness 0/1 and has indestructible, and it loses all other abilities, card types, and creature types.

Sol Ring

Archon of Falling Stars

Flying
When Archon of Falling Stars dies, you may return target enchantment card from your graveyard to the battlefield.

Auramancer

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

Three Dreams

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