Plains

Composer of Spring

Constellation — Whenever an enchantment you control enters, you may put a land card from your hand onto the battlefield tapped. If you control six or more enchantments, instead you may put a creature or land card from your hand onto the battlefield tapped.

Cacophony Unleashed

When Cacophony Unleashed enters, if you cast it, destroy all nonenchantment creatures.
Whenever Cacophony Unleashed or another enchantment you control enters, until end of turn, Cacophony Unleashed becomes a legendary 6/6 Nightmare God creature with menace and deathtouch. It's still an enchantment.

Eidolon of Blossoms

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

Anikthea, Hand of Erebos

Menace
Other enchantment creatures you control have menace.
Whenever Anikthea enters or attacks, exile up to one target non-Aura enchantment card from your graveyard. Create a token that's a copy of that card, except it's a 3/3 black Zombie creature in addition to its other types.

Swamp

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.

Sanctum Weaver

{T}: Add X mana of any one color, where X is the number of enchantments you control.

Yenna, Redtooth Regent

{2}, {T}: Choose target enchantment you control that doesn't have the same name as another permanent you control. Create a token that's a copy of it, except it isn't legendary. If the token is an Aura, untap Yenna, Redtooth Regent, then scry 2. Activate only as a sorcery.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

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.

Demon of Fate's Design

Flying, trample
Once during each of your turns, you may cast an enchantment spell by paying life equal to its mana value rather than paying its mana cost.
{2}{B}, Sacrifice another enchantment: Demon of Fate's Design gets +X/+0 until end of turn, where X is the sacrificed enchantment's mana value.