Have

Towering-Wave Mystic

Whenever this creature deals damage, target player mills that many cards.

Didn't Say Please

Counter target spell. Its controller mills three cards.

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Stormbound Geist

Flying
This creature can block only creatures with flying.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Relic of Progenitus

{T}: Target player exiles a card from their graveyard.
{1}, Exile this artifact: Exile all graveyards. Draw a card.

Sage's Row Denizen

Whenever another blue creature you control enters, target player mills two cards.

Lonely Sandbar

This land enters tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

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.)

Getting

Jace's Phantasm

Flying
This creature gets +4/+4 as long as an opponent has ten or more cards in their graveyard.

Tome Scour

Island

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

Annul

Counter target artifact or enchantment spell.

Compelling Argument

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

Vapor Snag

Return target creature to its owner's hand. Its controller loses 1 life.

Mystic Sanctuary

({T}: Add {U}.)
This land enters tapped unless you control three or more other Islands.
When this land enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Thought Scour

Target player mills two cards.
Draw a card.

Shriekgeist

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

Snap

Return target creature to its owner's hand. Untap up to two lands.

Coral Net

Enchant green or white creature
Enchanted creature has "At the beginning of your upkeep, sacrifice this creature unless you discard a card."