Ancestral Recall

Iona, Shield of Emeria

Flying
As Iona, Shield of Emeria enters, choose a color.
Your opponents can't cast spells of the chosen color.

Mox Pearl

Tolarian Academy

{T}: Add {U} for each artifact you control.

Time Walk

Upheaval

Return all permanents to their owners' hands.

Erayo's Essence

Whenever an opponent casts their first spell each turn, counter that spell.

Erayo, Soratami Ascendant

Flying
Whenever the fourth spell of a turn is cast, flip Erayo, Soratami Ascendant.

Erayo, Soratami Ascendant // Erayo's Essence

Library of Alexandria

{T}: Add {C}.
{T}: Draw a card. Activate only if you have exactly seven cards in hand.

Limited Resources

When Limited Resources enters, each player chooses five lands they control and sacrifices the rest.
Players can't play lands as long as ten or more lands are on the battlefield.

Mox Sapphire

Shahrazad

Players play a Magic subgame, using their libraries as their decks. Each player who doesn't win the subgame loses half their life, rounded up.

Trade Secrets

Target opponent draws two cards, then you draw up to four cards. That opponent may repeat this process as many times as they choose.

Paradox Engine

Whenever you cast a spell, untap all nonland permanents you control.

Nadu, Winged Wisdom

Flying
Creatures you control have "Whenever this creature becomes the target of a spell or ability, reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put it into your hand. This ability triggers only twice each turn."

Mox Jet

Time Vault

Time Vault enters tapped.
Time Vault doesn't untap during your untap step.
If you would begin your turn while Time Vault is tapped, you may skip that turn instead. If you do, untap Time Vault.
{T}: Take an extra turn after this one.