Demand Answers

As an additional cost to cast this spell, sacrifice an artifact or discard a card.
Draw two cards.

Island

Grindstone

{3}, {T}: Target player mills two cards. If two cards that share a color were milled this way, repeat this process.

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Swamp

Simian Spirit Guide

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.)

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Dark Ritual

Mountain

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.")

Mesmeric Orb

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