Snow-Covered Swamp

Rimebound Dead

{S}: Regenerate Rimebound Dead. ({S} can be paid with one mana from a snow source.)

Cabal Coffers

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

Wall of Bone

Defender (This creature can't attack.)
{B}: Regenerate Wall of Bone. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Clattering Augur

Clattering Augur can't block.
When Clattering Augur enters, you draw a card and you lose 1 life.
{2}{B}{B}: Return Clattering Augur from your graveyard to your hand.

Tenacious Dead

When Tenacious Dead dies, you may pay {1}{B}. If you do, return it to the battlefield tapped under its owner's control.

Death Baron

Skeletons you control and other Zombies you control get +1/+1 and have deathtouch. (Any amount of damage they deal to a creature is enough to destroy it.)

Barrier of Bones

Defender
When Barrier of Bones enters, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Urborg, Tomb of Yawgmoth

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

Manor Skeleton

Grim Roustabout

Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)
{1}{B}: Regenerate Grim Roustabout.

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.)