Drannith Magistrate

Your opponents can't cast spells from anywhere other than their hands.

Conspicuous Snoop

Play with the top card of your library revealed.
You may cast Goblin spells from the top of your library.
As long as the top card of your library is a Goblin card, Conspicuous Snoop has all activated abilities of that card.

Eidolon of Rhetoric

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

Winota, Joiner of Forces

Whenever a non-Human creature you control attacks, look at the top six cards of your library. You may put a Human creature card from among them onto the battlefield tapped and attacking. It gains indestructible until end of turn. Put the rest of the cards on the bottom of your library in a random order.

Combat Celebrant

If Combat Celebrant hasn't been exerted this turn, you may exert it as it attacks. When you do, untap all other creatures you control and after this phase, there is an additional combat phase. (An exerted creature won't untap during your next untap step.)

Ethersworn Canonist

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

Aven Mindcensor

Flash
Flying
If an opponent would search a library, that player searches the top four cards of that library instead.

Archon of Emeria

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

Dockside Extortionist

When Dockside Extortionist enters, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")