Bayou

Yavimaya, Cradle of Growth

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

Insidious Roots

Creature tokens you control have "{T}: Add one mana of any color."
Whenever one or more creature cards leave your graveyard, create a 0/1 green Plant creature token, then put a +1/+1 counter on each Plant you control.

Overgrown Tomb

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

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

Cabal Coffers

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

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Champion of the Perished

Whenever another Zombie you control enters, put a +1/+1 counter on Champion of the Perished.

Urborg, Tomb of Yawgmoth

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

Stitcher's Supplier

When Stitcher's Supplier enters or dies, mill three cards. (Put the top three cards of your library into your graveyard.)

Grim Tutor

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.

Cabal Stronghold

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

Gravecrawler

Gravecrawler can't block.
You may cast Gravecrawler from your graveyard as long as you control a Zombie.

Bridge from Below

Whenever a nontoken creature is put into your graveyard from the battlefield, if Bridge from Below is in your graveyard, create a 2/2 black Zombie creature token.
When a creature is put into an opponent's graveyard from the battlefield, if Bridge from Below is in your graveyard, exile Bridge from Below.

Castle Locthwain

Castle Locthwain enters tapped unless you control a Swamp.
{T}: Add {B}.
{1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.