Hidden Spider

When an opponent casts a creature spell with flying, if Hidden Spider is an enchantment, Hidden Spider becomes a 3/5 Spider creature with reach. (It can block creatures with flying.)

Genju of the Fields

Enchant Plains
{2}: Until end of turn, enchanted Plains becomes a 2/5 white Spirit creature with "Whenever this creature deals damage, its controller gains that much life." It's still a land.
When enchanted Plains is put into a graveyard, you may return Genju of the Fields from your graveyard to your hand.

Hidden Herd

When an opponent plays a nonbasic land, if Hidden Herd is an enchantment, Hidden Herd becomes a 3/3 Beast creature.

Case of the Locked Hothouse

You may play an additional land on each of your turns.
To solve — You control seven or more lands. (If unsolved, solve at the beginning of your end step.)
Solved — You may look at the top card of your library any time, and you may play lands and cast creature and enchantment spells from the top of your library.

Opal Acrolith

Whenever an opponent casts a creature spell, if Opal Acrolith is an enchantment, Opal Acrolith becomes a 2/4 Soldier creature.
{0}: Opal Acrolith becomes an enchantment.

Hidden Gibbons

When an opponent casts an instant spell, if Hidden Gibbons is an enchantment, Hidden Gibbons becomes a 4/4 Ape creature.

Opal Titan

When an opponent casts a creature spell, if Opal Titan is an enchantment, Opal Titan becomes a 4/4 Giant creature with protection from each of that spell's colors.

Enchantress's Presence

Whenever you cast an enchantment spell, draw a card.

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.

Opal Avenger

When you have 10 or less life, if Opal Avenger is an enchantment, Opal Avenger becomes a 3/5 Soldier creature.

Nissa's Zendikon

Enchant land
Enchanted land is a 4/4 Elemental creature with reach and haste. It's still a land.
When enchanted land dies, return that card to its owner's hand.

Sigil of the Empty Throne

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

Guardian Zendikon

Enchant land
Enchanted land is a 2/6 white Wall creature with defender. It's still a land.
When enchanted land dies, return that card to its owner's hand.

Command Tower

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

Forest

Opal Archangel

When an opponent casts a creature spell, if Opal Archangel is an enchantment, Opal Archangel becomes a 5/5 Angel creature with flying and vigilance.

Hidden Guerrillas

When an opponent casts an artifact spell, if Hidden Guerrillas is an enchantment, Hidden Guerrillas becomes a 5/3 Soldier creature with trample.

Plains

Still Life

{G}{G}: Still Life becomes a 4/3 Centaur creature in addition to its other types until end of turn.

Selesnya Guildgate

This land enters tapped.
{T}: Add {G} or {W}.

Hidden Predators

When an opponent controls a creature with power 4 or greater, if Hidden Predators is an enchantment, Hidden Predators becomes a 4/4 Beast creature.

Myth Realized

Whenever you cast a noncreature spell, put a lore counter on Myth Realized.
{2}{W}: Put a lore counter on Myth Realized.
{W}: Until end of turn, Myth Realized becomes a Monk Avatar creature in addition to its other types and gains "This creature's power and toughness are each equal to the number of lore counters on it."

Genju of the Cedars

Enchant Forest
{2}: Enchanted Forest becomes a 4/4 green Spirit creature until end of turn. It's still a land.
When enchanted Forest is put into a graveyard, you may return Genju of the Cedars from your graveyard to your hand.

Opalescence

Each other non-Aura enchantment is a creature in addition to its other types and has base power and base toughness each equal to its mana value.

Opal Gargoyle

When an opponent casts a creature spell, if Opal Gargoyle is an enchantment, Opal Gargoyle becomes a 2/2 Gargoyle creature with flying.

Living Terrain

Enchant land
Enchanted land is a 5/6 green Treefolk creature that's still a land.

Hidden Ancients

When an opponent casts an enchantment spell, if Hidden Ancients is an enchantment, Hidden Ancients becomes a 5/5 Treefolk creature.

Opal Champion

When an opponent casts a creature spell, if Opal Champion is an enchantment, Opal Champion becomes a 3/3 Knight creature with first strike.

Sterling Grove

Other enchantments you control have shroud. (They can't be the targets of spells or abilities.)
{1}, Sacrifice Sterling Grove: Search your library for an enchantment card, reveal it, then shuffle and put that card on top.

Opal Guardian

When an opponent casts a creature spell, if Opal Guardian is an enchantment, Opal Guardian becomes a 3/4 Gargoyle creature with flying and protection from red.

Vastwood Zendikon

Enchant land
Enchanted land is a 6/4 green Elemental creature. It's still a land.
When enchanted land dies, return that card to its owner's hand.

Opal Caryatid

When an opponent casts a creature spell, if Opal Caryatid is an enchantment, Opal Caryatid becomes a 2/2 Soldier creature.

Sythis, Harvest's Hand

Whenever you cast an enchantment spell, you gain 1 life and draw a card.

Hidden Stag

Whenever an opponent plays a land, if Hidden Stag is an enchantment, Hidden Stag becomes a 3/2 Elk Beast creature.
Whenever you play a land, if Hidden Stag is a creature, Hidden Stag becomes an enchantment.