Rule of Law

Each player can't cast more than one spell each turn.

Containment Priest

Flash
If a nontoken creature would enter and it wasn't cast, exile it instead.

Archon of Emeria

Flying
Each player can't cast more than one spell each turn.
Nonbasic lands your opponents control enter tapped.

Narset, Parter of Veils

Each opponent can't draw more than one card each turn.
−2: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Deafening Silence

Each player can't cast more than one noncreature spell each turn.

Moderation

You can't cast more than one spell each turn.
Whenever you cast a spell, draw a card.

Lavinia, Azorius Renegade

Each opponent can't cast noncreature spells with mana value greater than the number of lands that player controls.
Whenever an opponent casts a spell, if no mana was spent to cast it, counter that spell.

Dream Trawler

Flying, lifelink
Whenever you draw a card, this creature gets +1/+0 until end of turn.
Whenever this creature attacks, draw a card.
Discard a card: This creature gains hexproof until end of turn. Tap it.