Archon of Emeria

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

Eidolon of Rhetoric

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

Deafening Silence

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

Rule of Law

Arcane Laboratory

Phyrexian Censor

Each player can't cast more than one non-Phyrexian spell each turn.
Non-Phyrexian creatures enter tapped.

Ethersworn Canonist

Each player who has cast a nonartifact spell this turn can't cast additional nonartifact spells.

High Noon

Each player can't cast more than one spell each turn.
{4}{R}, Sacrifice this enchantment: It deals 5 damage to any target.

Najeela, the Blade-Blossom

Whenever a Warrior attacks, you may have its controller create a 1/1 white Warrior creature token that's tapped and attacking.
{W}{U}{B}{R}{G}: Untap all attacking creatures. They gain trample, lifelink, and haste until end of turn. After this phase, there is an additional combat phase. Activate only during combat.