Light of Day

Roots of Life

As Roots of Life enters, choose Island or Swamp.
Whenever a land of the chosen type an opponent controls becomes tapped, you gain 1 life.

Royal Decree

Cumulative upkeep {W} (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.)
Whenever a Swamp, Mountain, black permanent, or red permanent becomes tapped, Royal Decree deals 1 damage to that permanent's controller.

Reap

Return up to X target cards from your graveyard to your hand, where X is the number of black permanents target opponent controls as you cast this spell.

Urborg, Tomb of Yawgmoth

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

Stern Judge

{T}: Each player loses 1 life for each Swamp they control.

Rune of Protection: Black

{W}: The next time a black source of your choice would deal damage to you this turn, prevent that damage.
Cycling {2} ({2}, Discard this card: Draw a card.)

Spreading Algae

Enchant Swamp
When enchanted land becomes tapped, destroy it.
When Spreading Algae is put into a graveyard from the battlefield, return Spreading Algae to its owner's hand.

Circle of Protection: Black

{1}: The next time a black source of your choice would deal damage to you this turn, prevent that damage.

Reclamation

Black creatures can't attack unless their controller sacrifices a land for each black creature they control that's attacking. (This cost is paid as attackers are declared.)

Compost

Whenever a black card is put into an opponent's graveyard from anywhere, you may draw a card.

Wash Out

Return all permanents of the color of your choice to their owners' hands.

Painter's Servant

As Painter's Servant enters, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

Pygmy Kavu

When Pygmy Kavu enters, draw a card for each black creature your opponents control.

Sway of Illusion

Any number of target creatures become the color of your choice until end of turn.
Draw a card.

Shifting Sky

As Shifting Sky enters, choose a color.
All nonland permanents are the chosen color.

Karma

At the beginning of each player's upkeep, Karma deals damage to that player equal to the number of Swamps they control.