Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Didn't Say Please

Counter target spell. Its controller mills three cards.

Thought Scour

Target player mills two cards.
Draw a card.

Jace's Erasure

Whenever you draw a card, you may have target player mill a card.

Zulaport Duelist

Flash
When Zulaport Duelist enters, up to one target creature gets -2/-0 until end of turn. Its controller mills two cards. (They put the top two cards of their library into their graveyard.)

Horrifying Revelation

Target player discards a card, then mills a card.

Mind Sculpt

Tome Scour

Pilfered Plans

Target player mills two cards. Draw two cards.

Island

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.)

Swamp

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.)

Stream of Thought

Target player mills four cards. You shuffle up to four cards from your graveyard into your library.
Replicate {2}{U}{U} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)