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.)

Pact of Negation

Counter target spell.
At the beginning of your next upkeep, pay {3}{U}{U}. If you don't, you lose the game.

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, this artifact deals 3 damage to you.
{T}: Add {C}{C}.

Jeweled Lotus

{T}, Sacrifice this artifact: Add three mana of any one color. Spend this mana only to cast your commander.

Mana Vault

This artifact doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {4}. If you do, untap this artifact.
At the beginning of your draw step, if this artifact is tapped, it deals 1 damage to you.
{T}: Add {C}{C}{C}.

Leyline of Anticipation

If this card is in your opening hand, you may begin the game with it on the battlefield.
You may cast spells as though they had flash.

Maddening Cacophony

Kicker {3}{U}
Each opponent mills eight cards. If this spell was kicked, instead each opponent mills half their library, rounded up.