Codex Shredder

{T}: Target player mills a card. (They put the top card of their library into their graveyard.)
{5}, {T}, Sacrifice Codex Shredder: Return target card from your graveyard to your hand.

Hedron Crab

Landfall — Whenever a land enters the battlefield under your control, target player mills three cards.

Island

Tome Scour

Keening Stone

{5}, {T}: Target player mills X cards, where X is the number of cards in that player's graveyard.

Ruin Crab

Landfall — Whenever a land enters the battlefield under your control, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Elixir of Immortality

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

Mind Sculpt

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.

Wall of Frost

Defender
Whenever Wall of Frost blocks a creature, that creature doesn't untap during its controller's next untap step.

Dreamscape Artist

{2}{U}, {T}, Discard a card, Sacrifice a land: Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Counterspell

The Chain Veil

At the beginning of your end step, if you didn't activate a loyalty ability of a planeswalker this turn, you lose 2 life.
{4}, {T}: For each planeswalker you control, you may activate one of its loyalty abilities once this turn as though none of its loyalty abilities have been activated this turn.

Traumatize

Target player mills half their library, rounded down.

Drowned Secrets

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

Fascination

Choose one —
• Each player draws X cards.
• Each player mills X cards.

Drown in Shapelessness

Return target creature to its owner's hand.

Jace, Memory Adept

+1: Draw a card. Target player mills a card.
0: Target player mills ten cards.
−7: Any number of target players each draw twenty cards.

Doubling Cube

{3}, {T}: Double the amount of each type of unspent mana you have.

Lier, Disciple of the Drowned

Spells can't be countered.
Each instant and sorcery card in your graveyard has flashback. The flashback cost is equal to that card's mana cost.

Purple-Crystal Crab

When Purple-Crystal Crab dies, draw a card.

Archive Trap

If an opponent searched their library this turn, you may pay {0} rather than pay this spell's mana cost.
Target opponent mills thirteen cards.

Giant Crab

{U}: Giant Crab gains shroud until end of turn. (It can't be the target of spells or abilities.)

Ancient Crab

Fortress Crab

Jace's Sanctum

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Curse of the Bloody Tome

Enchant player
At the beginning of enchanted player's upkeep, that player mills two cards.

Echoing Truth

Return target nonland permanent and all other permanents with the same name as that permanent to their owners' hands.

Shriekgeist

Flying
Whenever Shriekgeist deals combat damage to a player, that player mills two cards.

Wishcoin Crab

Horseshoe Crab

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Unsummon

Mirrorshell Crab

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)
Channel — {2}{U}, Discard Mirrorshell Crab: Counter target spell or ability unless its controller pays {3}.

Cavalier of Gales

Flying
When Cavalier of Gales enters the battlefield, draw three cards, then put two cards from your hand on top of your library in any order.
When Cavalier of Gales dies, shuffle it into its owner's library, then scry 2.

Jace's Archivist

{U}, {T}: Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Jace's Phantasm

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

Mindshrieker

Flying
{2}: Target player mills a card. Mindshrieker gets +X/+X until end of turn, where X is the milled card's mana value.

Paragon of Gathering Mists

Other blue creatures you control get +1/+1.
{U}, {T}: Another target blue creature you control gains flying until end of turn.