Mirko Vosk, Mind Drinker

Flying
Whenever Mirko Vosk, Mind Drinker deals combat damage to a player, that player reveals cards from the top of their library until they reveal four land cards, then puts those cards into their graveyard.

Thoughtcutter Agent

{U}{B}, {T}: Target player loses 1 life and reveals their hand.

Patient Rebuilding

At the beginning of your upkeep, target opponent mills three cards, then you draw a card for each land card put into their graveyard this way.

Horrifying Revelation

Target player discards a card, then mills a card.

Chronic Flooding

Enchant land
Whenever enchanted land becomes tapped, its controller mills three cards.

Paranoid Delusions

Target player mills three cards.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Memory Erosion

Whenever an opponent casts a spell, that player mills two cards.

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.)

Pilfered Plans

Target player mills two cards. Draw two cards.

Counterspell

Island

Swamp

Didn't Say Please

Counter target spell. Its controller mills three cards.

Tome Scour

Psychic Strike

Counter target spell. Its controller mills two cards.

Curse of the Bloody Tome

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

Psychic Corrosion

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

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.