Urborg, Tomb of Yawgmoth

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

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Navigation Orb

{2}, {T}, Sacrifice this artifact: Search your library for up to two basic land cards and/or Gate cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Magus of the Coffers

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

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

Expedition Map

{2}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Nirkana Revenant

Whenever you tap a Swamp for mana, add an additional {B}.
{B}: This creature gets +1/+1 until end of turn.

Crowded Crypt

{T}: Add {B}.
Whenever a creature you control dies, put a corpse counter on this artifact.
{4}{B}{B}, {T}, Sacrifice this artifact: Create a 2/2 black Zombie creature token with decayed for each corpse counter on this artifact. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)

Infernal Idol

{T}: Add {B}.
{1}{B}{B}, {T}, Sacrifice this artifact: You draw two cards and you lose 2 life.

Walking Atlas

{T}: You may put a land card from your hand onto the battlefield.

Gauntlet of Power

As this artifact enters, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

Wayfarer's Bauble

{2}, {T}, Sacrifice this artifact: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Thespian's Stage

{T}: Add {C}.
{2}, {T}: This land becomes a copy of target land, except it has this ability.

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.

Cabal Coffers

Extraplanar Lens

Imprint — When this artifact enters, you may exile target land you control.
Whenever a land with the same name as the exiled card is tapped for mana, its controller adds one mana of any type that land produced.

Rain of Filth

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

Arcane Signet

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

Vesuva

You may have this land enter tapped as a copy of any land on the battlefield.

Cabal Stronghold

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

Caged Sun

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Sol Ring

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.