Drowned Secrets

Whenever you cast a blue spell, target player mills two cards.

Take Inventory

Draw a card, then draw cards equal to the number of cards named Take Inventory in your graveyard.

Psychic Corrosion

Whenever you draw a card, each opponent mills two cards.

Essence Scatter

Drag Under

Return target creature to its owner's hand.
Draw a card.

Divination

Warped Landscape

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Vessel of Paramnesia

{U}, Sacrifice this enchantment: Target player mills three cards. Draw a card.

Mind Sculpt

Stormtide Leviathan

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.

Silent Observer

Compelling Argument

Target player mills five cards.
Cycling {U} ({U}, Discard this card: Draw a card.)

Manic Scribe

When this creature enters, each opponent mills three cards.
Delirium — At the beginning of each opponent's upkeep, if there are four or more card types among cards in your graveyard, that player mills three cards.

Fraying Sanity

Enchant player
At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

Persistent Nightmare

Skulk (This creature can't be blocked by creatures with greater power.)
When this creature deals combat damage to a player, return it to its owner's hand.

Startled Awake

Target opponent mills thirteen cards.
{3}{U}{U}: Put this card from your graveyard onto the battlefield transformed. Activate only as a sorcery.

Startled Awake // Persistent Nightmare

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Pull from Tomorrow

Guardians of Meletis

Chilling Chronicle

{1}, {T}: Tap target nonland permanent. Transform this artifact.

Mysterious Tome

{2}, {T}: Draw a card. Transform this artifact.

Mysterious Tome // Chilling Chronicle

Island

Niblis of Frost

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast an instant or sorcery spell, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.