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.)

War Tax

{X}{U}: This turn, creatures can't attack unless their controller pays {X} for each attacking creature they control.

Jace's Erasure

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

Propaganda

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

Curse of Echoes

Enchant player
Whenever enchanted player casts an instant or sorcery spell, each other player may copy that spell and may choose new targets for the copy they control.

Underground Sea

Lotus Petal

{T}, Sacrifice this artifact: Add one mana of any color.

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.

Ever-Watching Threshold

Whenever an opponent attacks, if they attacked you and/or a planeswalker you control, draw a card.

Nephalia Drownyard

{T}: Add {C}.
{1}{U}{B}, {T}: Target player mills three cards.

Fog Bank

Defender (This creature can't attack.)
Flying
Prevent all combat damage that would be dealt to and dealt by this creature.

Island

Watery Grave

({T}: Add {U} or {B}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

No Mercy

Whenever a creature deals damage to you, destroy it.

Restless Reef

This land enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}: Until end of turn, this land becomes a 4/4 blue and black Shark creature with deathtouch. It's still a land.
Whenever this land attacks, target player mills four cards.

Swamp

Wall of Lost Thoughts

Defender (This creature can't attack.)
When this creature enters, target player mills four cards. (They put the top four cards of their library into their graveyard.)