Opposition Agent

Flash
You control your opponents while they're searching their libraries.
While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Notion Thief

Flash
If an opponent would draw a card except the first one they draw in each of their draw steps, instead that player skips that draw and you draw a card.

Tocatli Honor Guard

Creatures entering don't cause abilities to trigger.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Torpor Orb

Mana Leak

Counter target spell unless its controller pays {3}.

Dawn of Hope

Whenever you gain life, you may pay {2}. If you do, draw a card.
{3}{W}: Create a 1/1 white Soldier creature token with lifelink.

Blind Obedience

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Artifacts and creatures your opponents control enter tapped.

Counterspell

Authority of the Consuls

Creatures your opponents control enter tapped.
Whenever a creature an opponent controls enters, you gain 1 life.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Oloro, Ageless Ascetic

At the beginning of your upkeep, you gain 2 life.
Whenever you gain life, you may pay {1}. If you do, draw a card and each opponent loses 1 life.
At the beginning of your upkeep, if Oloro, Ageless Ascetic is in the command zone, you gain 2 life.

Hushbringer

Flying, lifelink
Creatures entering or dying don't cause abilities to trigger.

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.

Linvala, Keeper of Silence

Flying
Activated abilities of creatures your opponents control can't be activated.

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.