Deep Gnome Terramancer

Flash
Mold Earth — Whenever one or more lands enter under an opponent's control without being played, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle. Do this only once each turn.

Atraxa, Grand Unifier

Flying, vigilance, deathtouch, lifelink
When Atraxa enters, reveal the top ten cards of your library. For each card type, you may put a card of that type from among the revealed cards into your hand. Put the rest on the bottom of your library in a random order. (Artifact, battle, creature, enchantment, instant, land, planeswalker, and sorcery are card types.)

Kataki, War's Wage

All artifacts have "At the beginning of your upkeep, sacrifice this artifact unless you pay {1}."

Doorkeeper Thrull

Flash
Flying
Artifacts and creatures entering don't cause abilities to trigger.

Stasis

Players skip their untap steps.
At the beginning of your upkeep, sacrifice this enchantment unless you pay {U}.

Charismatic Conqueror

Vigilance
Whenever an artifact or creature an opponent controls enters untapped, they may tap that permanent. If they don't, you create a 1/1 white Vampire creature token with lifelink.

Mangara, the Diplomat

Lifelink
Whenever an opponent attacks with creatures, if two or more of those creatures are attacking you and/or planeswalkers you control, draw a card.
Whenever an opponent casts their second spell each turn, draw a card.

Aven Mindcensor

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

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Archon of Emeria

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

Voice of Victory

Mobilize 2 (Whenever this creature attacks, create two tapped and attacking 1/1 red Warrior creature tokens. Sacrifice them at the beginning of the next end step.)
Your opponents can't cast spells during your turn.

Lotho, Corrupt Shirriff

Whenever a player casts their second spell each turn, you lose 1 life and create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Keeper of the Accord

At the beginning of each opponent's end step, if that player controls more creatures than you, create a 1/1 white Soldier creature token.
At the beginning of each opponent's end step, if that player controls more lands than you, you may search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Seedborn Muse

Untap all permanents you control during each other player's untap step.

Michiko Konda, Truth Seeker

Whenever a source an opponent controls deals damage to you, that player sacrifices a permanent of their choice.

Ranger-Captain of Eos

When this creature enters, you may search your library for a creature card with mana value 1 or less, reveal it, put it into your hand, then shuffle.
Sacrifice this creature: Your opponents can't cast noncreature spells this turn.

Dauntless Dismantler

Artifacts your opponents control enter tapped.
{X}{X}{W}, Sacrifice this creature: Destroy each artifact with mana value X.

Collector Ouphe

Activated abilities of artifacts can't be activated.

Permission Denied

Counter target noncreature spell. Your opponents can't cast noncreature spells this turn.

Thalia, Heretic Cathar

First strike
Creatures and nonbasic lands your opponents control enter tapped.

Leonin Arbiter

Players can't search libraries. Any player may pay {2} for that player to ignore this effect until end of turn.

Elesh Norn, Mother of Machines

Vigilance
If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Permanents entering don't cause abilities of permanents your opponents control to trigger.

Myrel, Shield of Argive

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.
Whenever Myrel attacks, create X 1/1 colorless Soldier artifact creature tokens, where X is the number of Soldiers you control.

Grand Abolisher

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.

Windborn Muse

Flying
Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.