Sickening Dreams

As an additional cost to cast this spell, discard X cards.
Sickening Dreams deals X damage to each creature and each player.

Ad Nauseam

Reveal the top card of your library and put that card into your hand. You lose life equal to its mana value. You may repeat this process any number of times.

Feast of Sanity

Whenever you discard a card, this enchantment deals 1 damage to any target and you gain 1 life.

Shadow of the Grave

Return to your hand all cards in your graveyard that you cycled or discarded this turn.

Ornithopter

Field of Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle this artifact and your graveyard into their owner's library.

Guildless Commons

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {C}{C}.

Buried Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Return target artifact card from your graveyard to your hand.

Dark Ritual

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Glacial Chasm

Cumulative upkeep—Pay 2 life. (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.)
When this land enters, sacrifice a land.
Creatures you control can't attack.
Prevent all damage that would be dealt to you.

Swamp

Rain of Filth

Until end of turn, lands you control gain "Sacrifice this land: Add {B}."

Dark Sphere

{T}, Sacrifice this artifact: The next time a source of your choice would deal damage to you this turn, prevent half that damage, rounded down.

Memnite

Sol Ring

Spellbook

Feldon's Cane

{T}, Exile this artifact: Shuffle your graveyard into your library.

Varragoth, Bloodsky Sire

Deathtouch
Boast — {1}{B}: Target player searches their library for a card, then shuffles and puts that card on top. (Activate only if this creature attacked this turn and only once each turn.)