Eon Hub

Lotus Petal

{T}, Sacrifice this artifact: Add one mana of any color.

Bile Blight

Target creature and all other creatures with the same name as that creature get -3/-3 until end of turn.

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.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Culling the Weak

As an additional cost to cast this spell, sacrifice a creature.
Add {B}{B}{B}{B}.

Sickening Dreams

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

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.

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.

Zombie Infestation

Discard two cards: Create a 2/2 black Zombie creature token.

Dark Ritual

Zombie

Maralen of the Mornsong

Players can't draw cards.
At the beginning of each player's draw step, that player loses 3 life, searches their library for a card, puts it into their hand, then shuffles.

Rain of Filth

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

Elixir of Immortality

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

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Ob Nixilis, Unshackled

Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis.

Boseiju, Who Shelters All

Boseiju enters tapped.
{T}, Pay 2 life: Add {C}. If that mana is spent on an instant or sorcery spell, that spell can't be countered.

Swamp

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.

Stunning Reversal

The next time you would lose the game this turn, instead draw seven cards and your life total becomes 1.
Exile Stunning Reversal.

Zulaport Cutthroat

Whenever this creature or another creature you control dies, each opponent loses 1 life and you gain 1 life.