Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Mirelurk Queen

Vigilance
When Mirelurk Queen enters, target player gets two rad counters.
Whenever one or more nonland cards are milled, draw a card, then put a +1/+1 counter on Mirelurk Queen. This ability triggers only once each turn.

Relic of Progenitus

{T}: Target player exiles a card from their graveyard.
{1}, Exile Relic of Progenitus: Exile all graveyards. Draw a card.

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Thought Collapse

Counter target spell. Its controller mills three cards.

Bruvac the Grandiloquent

If an opponent would mill one or more cards, they mill twice that many cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Ruin Crab

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

Fleet Swallower

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

Persistent Petitioners

{1}, {T}: Target player mills a card. (They put the top card of their library into their graveyard.)
Tap four untapped Advisors you control: Target player mills twelve cards.
A deck can have any number of cards named Persistent Petitioners.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Sphinx's Tutelage

Whenever you draw a card, target opponent mills two cards. If two nonland cards that share a color were milled this way, repeat this process.
{5}{U}: Draw a card, then discard a card.

Sky Diamond

Zellix, Sanity Flayer

Hive Mind — Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.
{1}, {T}: Target player mills three cards.
Choose a Background (You can have a Background as a second commander.)

Dissipation Field

Whenever a permanent deals damage to you, return it to its owner's hand.

Sol Ring

Counterspell

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Mass Appeal

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Tasha's Hideous Laughter

Each opponent exiles cards from the top of their library until that player has exiled cards with total mana value 20 or more.

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.

Drowned Secrets

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

Raise the Palisade

Choose a creature type. Return all creatures that aren't of the chosen type to their owners' hands.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Sapphire Medallion

Blue spells you cast cost {1} less to cast.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters, untap all creatures.

Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Psychic Corrosion

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

Flare of Denial

You may sacrifice a nontoken blue creature rather than pay this spell's mana cost.
Counter target spell.

Grafdigger's Cage

Creature cards in graveyards and libraries can't enter the battlefield.
Players can't cast spells from graveyards or libraries.

Estrid's Invocation

You may have Estrid's Invocation enter as a copy of an enchantment you control, except it has "At the beginning of your upkeep, you may exile this enchantment. If you do, return it to the battlefield under its owner's control."

Windfall

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

Island

Evacuation

Return all creatures to their owners' hands.

Thassa's Oracle

When Thassa's Oracle enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Memory Erosion

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

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Mesmeric Orb

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Riddlekeeper

Whenever a creature attacks you or a planeswalker you control, that creature's controller mills two cards.