Doomsday

Search your library and graveyard for five cards and exile the rest. Put the chosen cards on top of your library in any order. You lose half your life, rounded up.

Psychosis Crawler

Psychosis Crawler's power and toughness are each equal to the number of cards in your hand.
Whenever you draw a card, each opponent loses 1 life.

Khalni Gem

When Khalni Gem enters, return two lands you control to their owner's hand.
{T}: Add two mana of any one color.

Devastating Dreams

As an additional cost to cast this spell, discard X cards at random.
Each player sacrifices X lands of their choice. Devastating Dreams deals X damage to each creature.

Sins of the Past

Until end of turn, you may cast target instant or sorcery card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead. Exile Sins of the Past.

Bloodstained Mire

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Platinum Angel

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

Drowned Catacomb

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

Underworld Dreams

Whenever an opponent draws a card, Underworld Dreams deals 1 damage to that player.

Arcane Signet

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

Hellcarver Demon

Flying
Whenever Hellcarver Demon deals combat damage to a player, sacrifice all other permanents you control and discard your hand. Exile the top six cards of your library. You may cast any number of spells from among cards exiled this way without paying their mana costs.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

Shadowborn Apostle

A deck can have any number of cards named Shadowborn Apostle.
{B}, Sacrifice six creatures named Shadowborn Apostle: Search your library for a Demon creature card, put it onto the battlefield, then shuffle.

Fetid Pools

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

Phyrexian Tyranny

Whenever a player draws a card, that player loses 2 life unless they pay {2}.

Command Tower

Insidious Dreams

As an additional cost to cast this spell, discard X cards.
Search your library for X cards, then shuffle and put those cards on top in any order.

Hive Mind

Whenever a player casts an instant or sorcery spell, each other player copies that spell. Each of those players may choose new targets for their copy.

Sphinx of the Chimes

Flying
Discard two nonland cards with the same name: Draw four cards.

Nekusar, the Mindrazer

At the beginning of each player's draw step, that player draws an additional card.
Whenever an opponent draws a card, Nekusar, the Mindrazer deals 1 damage to that player.

Sign in Blood

Target player draws two cards and loses 2 life.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Swamp

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Morality Shift

Exchange your graveyard and library. Then shuffle your library.

Decree of Annihilation

Exile all artifacts, creatures, and lands from the battlefield, all cards from all graveyards, and all cards from all hands.
Cycling {5}{R}{R} ({5}{R}{R}, Discard this card: Draw a card.)
When you cycle Decree of Annihilation, destroy all lands.

Gilded Lotus

Teferi, Mage of Zhalfir

Flash
Creature cards you own that aren't on the battlefield have flash.
Each opponent can cast spells only any time they could cast a sorcery.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)