Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards.

Memory Sluice

Target player mills four cards.
Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)

Annul

Counter target artifact or enchantment spell.

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.

Awoken Horror

When this creature transforms into Awoken Horror, return all non-Horror creatures to their owners' hands.

Thing in the Ice

Defender
Thing in the Ice enters with four ice counters on it.
Whenever you cast an instant or sorcery spell, remove an ice counter from Thing in the Ice. Then if it has no ice counters on it, transform it.

Thing in the Ice // Awoken Horror

Mana Leak

Counter target spell unless its controller pays {3}.

Ipnu Rivulet

{T}: Add {C}.
{T}, Pay 1 life: Add {U}.
{1}{U}, {T}, Sacrifice a Desert: Target player mills four cards. (They put the top four cards of their library into their graveyard.)

Mind Sculpt

Traumatize

Target player mills half their library, rounded down.

Persistent Nightmare

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

Startled Awake

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

Startled Awake // Persistent Nightmare

Dream Twist

Target player mills three cards.
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle Elixir of Immortality and your graveyard into their owner's library.

Jace's Phantasm

Flying
Jace's Phantasm gets +4/+4 as long as an opponent has ten or more cards in their graveyard.

Fog Bank

Defender (This creature can't attack.)
Flying
Prevent all combat damage that would be dealt to and dealt by this creature.

Dispel

Winds of Rebuke

Return target nonland permanent to its owner's hand. Each player mills two cards.