Tendrils of Corruption

Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.

Might Sliver

Shrouded Lore

Target opponent chooses a card in your graveyard. You may pay {B}. If you do, repeat this process except that opponent can't choose a card already chosen for Shrouded Lore. Then put the last chosen card into your hand.

Conspiracy

As Conspiracy enters, choose a creature type.
Creatures you control are the chosen type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Giant Dustwasp

Flying
Suspend 4—{1}{G} (Rather than cast this card from your hand, you may pay {1}{G} and exile it with four time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)

Forest

Pulmonic Sliver

All Sliver creatures have flying.
All Slivers have "If this permanent would be put into a graveyard, you may put it on top of its owner's library instead."

Sidewinder Sliver

All Sliver creatures have flanking. (Whenever a creature without flanking blocks a Sliver, the blocking creature gets -1/-1 until end of turn.)

Wrap in Vigor

Reflex Sliver

Gemhide Sliver

All Slivers have "{T}: Add one mana of any color."

Swamp

Thallid Shell-Dweller

Defender
At the beginning of your upkeep, put a spore counter on Thallid Shell-Dweller.
Remove three spore counters from Thallid Shell-Dweller: Create a 1/1 green Saproling creature token.

Utopia Mycon

At the beginning of your upkeep, put a spore counter on Utopia Mycon.
Remove three spore counters from Utopia Mycon: Create a 1/1 green Saproling creature token.
Sacrifice a Saproling: Add one mana of any color.

Damnation

Destroy all creatures. They can't be regenerated.

Plains

Darkheart Sliver

All Slivers have "Sacrifice this permanent: You gain 3 life."

Essence Sliver

Whenever a Sliver deals damage, its controller gains that much life.

Mirri the Cursed

Flying, first strike, haste
Whenever Mirri the Cursed deals combat damage to a creature, put a +1/+1 counter on Mirri the Cursed.

Magus of the Coffers

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

Grave Peril

When a nonblack creature enters, sacrifice Grave Peril. If you do, destroy that creature.

Vhati il-Dal

{T}: Until end of turn, target creature has base power 1 or base toughness 1.

Cradle to Grave

Destroy target nonblack creature that entered this turn.

Basal Sliver

All Slivers have "Sacrifice this permanent: Add {B}{B}."

Cloud Key

As Cloud Key enters, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.