Fellwar Stone

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

Ornithopter of Paradise

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp you control.

Arcane Signet

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

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Sol Ring

Swamp

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.

Ob Nixilis, Unshackled

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

Defense Grid

Each spell costs {3} more to cast except during its controller's turn.

Paradise Mantle

Equipped creature has "{T}: Add one mana of any color."
Equip {1}

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Roaming Throne

Ward {2}
As Roaming Throne enters, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

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.

Magus of the Coffers

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

Thought Vessel

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

Lightning Greaves

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

Platinum Angel

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

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Cabal Coffers

Leaden Myr

Urborg, Tomb of Yawgmoth

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

Cabal Ritual

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