Venomous Hierophant

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When this creature enters, mill three cards. (Put the top three cards of your library into your graveyard.)

Fruit of Tizerus

Target player loses 2 life.
Escape—{3}{B}, Exile three other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Starlit Mantle

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature you control
When this Aura enters, enchanted creature gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)
Enchanted creature gets +1/+1.

Nyxborn Seaguard

Omen of the Dead

Flash
When this enchantment enters, return target creature card from your graveyard to your hand.
{2}{B}, Sacrifice this enchantment: Scry 2.

Memory Drain

Thirst for Meaning

Draw three cards. Then discard two cards unless you discard an enchantment card.

Deny the Divine

Counter target creature or enchantment spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Chain to Memory

Target creature gets -4/-0 until end of turn. Scry 2.

Sweet Oblivion

Target player mills four cards.
Escape—{3}{U}, Exile four other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Devourer of Memory

Whenever one or more cards are put into your graveyard from your library, this creature gets +1/+1 until end of turn and can't be blocked this turn.
{1}{U}{B}: Mill a card.

Ichthyomorphosis

Enchant creature
Enchanted creature loses all abilities and is a blue Fish with base power and toughness 0/1.

Swamp

Sage of Mysteries

Constellation — Whenever an enchantment you control enters, target player mills two cards.

Island

Towering-Wave Mystic

Whenever this creature deals damage, target player mills that many cards.

Riptide Turtle

Glimpse of Freedom

Draw a card.
Escape—{2}{U}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Omen of the Sea

Flash (You may cast this spell any time you could cast an instant.)
When this enchantment enters, scry 2, then draw a card.
{2}{U}, Sacrifice this enchantment: Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Brine Giant

Affinity for enchantments (This spell costs {1} less to cast for each enchantment you control.)