Counterspell

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Desecration Elemental

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Whenever a player casts a spell, sacrifice a creature.

Jon Irenicus, Shattered One

At the beginning of your end step, target opponent gains control of up to one target creature you control. Put two +1/+1 counters on it and tap it. It's goaded for the rest of the game and it gains "This creature can't be sacrificed." (It attacks each combat if able and attacks a player other than you if able.)
Whenever a creature you own but don't control attacks, you draw a card.

Greater Harvester

At the beginning of your upkeep, sacrifice a permanent.
Whenever Greater Harvester deals combat damage to a player, that player sacrifices two permanents.

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Rotting Regisaur

At the beginning of your upkeep, discard a card.

Abyssal Persecutor

Flying, trample
You can't win the game and your opponents can't lose the game.

Choked Estuary

As Choked Estuary enters, you may reveal an Island or Swamp card from your hand. If you don't, Choked Estuary enters tapped.
{T}: Add {U} or {B}.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. Talisman of Dominance deals 1 damage to you.

Evil Eye of Urborg

Non-Eye creatures you control can't attack.
Whenever Evil Eye of Urborg becomes blocked by a creature, destroy that creature.

All Is Dust

Each player sacrifices all permanents they control that are one or more colors.

Ebon Drake

Flying
Whenever a player casts a spell, you lose 1 life.

Drowned Catacomb

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Changeling Outcast

Changeling (This card is every creature type.)
Changeling Outcast can't block and can't be blocked.

Archfiend of the Dross

Flying
Archfiend of the Dross enters with four oil counters on it.
At the beginning of your upkeep, remove an oil counter from Archfiend of the Dross. Then if it has no oil counters on it, you lose the game.
Whenever a creature an opponent controls dies, its controller loses 2 life.

Fetid Pools

({T}: Add {U} or {B}.)
Fetid Pools enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Snow-Covered Swamp

Unmarked Grave

Search your library for a nonlegendary card, put that card into your graveyard, then shuffle.

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker. Each player who can't discards a card.

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Slither Blade

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Infernal Grasp

Destroy target creature. You lose 2 life.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Exchange of Words

When Exchange of Words enters, choose two target creatures. For as long as Exchange of Words remains on the battlefield, exchange the text boxes of those creatures.

Thought Devourer

Flying
Your maximum hand size is reduced by four.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Sol Ring

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. Underground River deals 1 damage to you.

Negate

Thought Eater

Flying
Your maximum hand size is reduced by three.

Ebonblade Reaper

Whenever Ebonblade Reaper attacks, you lose half your life, rounded up.
Whenever Ebonblade Reaper deals combat damage to a player, that player loses half their life, rounded up.
Morph {3}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Fellwar Stone

Evil Eye of Orms-by-Gore

Non-Eye creatures you control can't attack.
Evil Eye of Orms-by-Gore can't be blocked except by Walls.

Dimir Signet

Blighted Agent

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Blighted Agent can't be blocked.

Flesh Reaver

Whenever Flesh Reaver deals damage to a creature or opponent, Flesh Reaver deals that much damage to you.

Assault Suit

Equipped creature gets +2/+2, has haste, can't attack you or planeswalkers you control, and can't be sacrificed.
At the beginning of each opponent's upkeep, you may have that player gain control of equipped creature until end of turn. If you do, untap it.
Equip {3}

Mystic Sanctuary

({T}: Add {U}.)
Mystic Sanctuary enters tapped unless you control three or more other Islands.
When Mystic Sanctuary enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Sower of Discord

Flying
As Sower of Discord enters, choose two players.
Whenever damage is dealt to one of the chosen players, the other chosen player also loses that much life.

Darkwater Catacombs

Snow-Covered Island

Diplomatic Immunity

Enchant creature
Shroud (A permanent with shroud can't be the target of spells or abilities.)
Enchanted creature has shroud.

Arcane Signet

Thought Vessel

Temple of Deceit

Temple of Deceit enters tapped.
When Temple of Deceit enters, scry 1.
{T}: Add {U} or {B}.

Drinker of Sorrow

Drinker of Sorrow can't block.
Whenever Drinker of Sorrow deals combat damage, sacrifice a permanent.

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Wrong Turn

Target opponent gains control of target creature. (If an attacking or blocking creature changes controllers, it's removed from combat.)