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.

Guardian's Magemark

Flash
Enchant creature
Creatures you control that are enchanted get +1/+1.

Transcendent Envoy

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

Battle Mastery

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

Mesa Enchantress

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

Rune of Sustenance

Enchant permanent
When Rune of Sustenance enters, draw a card.
As long as enchanted permanent is a creature, it has lifelink.
As long as enchanted permanent is an Equipment, it has "Equipped creature has lifelink."

Arrest

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

Indomitable Will

Flash
Enchant creature
Enchanted creature gets +1/+2.

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.

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.)

Flawless Maneuver

If you control a commander, you may cast this spell without paying its mana cost.
Creatures you control gain indestructible until end of turn.

Plains

Conviction

Enchant creature
Enchanted creature gets +1/+3.
{W}: Return Conviction to its owner's hand.

Triclopean Sight

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

Spirit Mantle

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

Promise of Loyalty

Each player puts a vow counter on a creature they control and sacrifices the rest. Each of those creatures can't attack you or planeswalkers you control for as long as it has a vow counter on it.

Pariah

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

Timely Ward

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

Shield of Duty and Reason

Enchant creature
Enchanted creature has protection from green and from blue.

Mask of Law and Grace

Enchant creature
Enchanted creature has protection from black and from red.

Armored Ascension

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

Saving Grace

Flash
Enchant creature you control
When Saving Grace enters, all damage that would be dealt this turn to you and permanents you control is dealt to enchanted creature instead.
Enchanted creature gets +0/+3.

Chains of Custody

Enchant creature you control
When Chains of Custody enters, exile target nonland permanent an opponent controls until Chains of Custody leaves the battlefield.
Enchanted creature has ward {2}. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)

Shielded by Faith

Enchant creature
Enchanted creature has indestructible.
Whenever a creature enters, you may attach Shielded by Faith to that creature.

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.

On Serra's Wings

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

Sol Ring

Cho-Manno's Blessing

Flash
Enchant creature
As Cho-Manno's Blessing enters, choose a color.
Enchanted creature has protection from the chosen color. This effect doesn't remove Cho-Manno's Blessing.

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.)

Benevolent Blessing

Flash
Enchant creature
As Benevolent Blessing enters, choose a color.
Enchanted creature has protection from the chosen color. This effect doesn't remove Auras and Equipment you control that are already attached to it.

Solid Footing

Flash
Enchant creature
Enchanted creature gets +1/+1.
As long as enchanted creature has vigilance, it assigns combat damage equal to its toughness rather than its power.

Ossification

Enchant basic land you control
When Ossification enters, exile target creature or planeswalker an opponent controls until Ossification leaves the battlefield.

Winds of Rath

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

Slash the Ranks

Destroy all creatures and planeswalkers except for commanders.

All That Glitters

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

Zealot's Conviction

Flash
Enchant creature
Enchanted creature gets +1/+1.
Corrupted — As long as an opponent has three or more poison counters, enchanted creature gets an additional +1/+0 and has first strike.

Skyblade's Boon

Enchant creature
Enchanted creature gets +1/+1 and has flying.
{2}{W}: Return Skyblade's Boon to its owner's hand. Activate only if Skyblade's Boon is on the battlefield or in your graveyard.

Sigil of the Empty Throne

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

Arcane Signet

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

Stoneskin

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

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.)

Divine Reckoning

Each player chooses a creature they control. Destroy the rest.
Flashback {5}{W}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.)

Sram, Senior Edificer

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

Ethereal Armor

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

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.

Gift of Granite

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +0/+2.

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.)

Military Discipline

Flash
Enchant creature
When Military Discipline enters, enchanted creature gains first strike until end of turn.
Enchanted creature gets +1/+0.

Starnheim Courser

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

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.

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.

Unquestioned Authority

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

Single Combat

Each player chooses a creature or planeswalker they control, then sacrifices the rest. Players can't cast creature or planeswalker spells until the end of your next turn.

Angelic Gift

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

Kor Spiritdancer

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

Petrify

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

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.

Flickerform

Enchant creature
{2}{W}{W}: Exile enchanted creature and all Auras attached to it. At the beginning of the next end step, return that card to the battlefield under its owner's control. If you do, return the other cards exiled this way to the battlefield under their owners' control attached to that creature.

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.

Cartouche of Solidarity

Enchant creature you control
When Cartouche of Solidarity enters, create a 1/1 white Warrior creature token with vigilance.
Enchanted creature gets +1/+1 and has first strike.

Archon of Sun's Grace

Flying, lifelink
Pegasus creatures you control have lifelink.
Constellation — Whenever an enchantment you control enters, create a 2/2 white Pegasus creature token with flying.

Teferi's Protection

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.)
Exile Teferi's Protection.

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.)

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.