Cavern of Souls

As Cavern of Souls enters the battlefield, choose a creature type. {T}: Add {1} to your mana pool. {T}: Add one mana of any color to your mana pool. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Collected Company

Look at the top six cards of your library. Put up to two creature cards with converted mana cost 3 or less from among them onto the battlefield. Put the rest on the bottom of your library in any order.

Sentinel Sliver

Sliver creatures you control have vigilance. (Attacking doesn't cause them to tap.)

Galerider Sliver

Sliver creatures you control have flying.

Syphon Sliver

Sliver creatures you control have lifelink. (Damage dealt by a Sliver creature you control also causes you to gain that much life.)

Blur Sliver

Sliver creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

Manaweft Sliver

Sliver creatures you control have "{T}: Add one mana of any color to your mana pool."

Predatory Sliver

Sliver creatures you control get +1/+1.

Diffusion Sliver

Whenever a Sliver creature you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {2}.

Sliver Hive

{T}: Add {1} to your mana pool. {T}: Add one mana of any color to your mana pool. Spend this mana only to cast a Sliver spell. {5}, {T}: Put a 1/1 colorless Sliver creature token onto the battlefield. Activate this ability only if you control a Sliver.

Sliver Hivelord

Sliver creatures you control have indestructible. (Damage and effects that say "destroy" don't destroy them.)

Aether Vial

At the beginning of your upkeep, you may put a charge counter on ?ther Vial. {T}: You may put a creature card with converted mana cost equal to the number of charge counters on ?ther Vial from your hand onto the battlefield.

Darkheart Sliver

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

Dormant Sliver

All Slivers have defender and "When this creature comes into play, draw a card."

Frenetic Sliver

All Slivers have "{0}: If this creature is in play, flip a coin. If you win the flip, remove this creature from the game and return it to play under its owner's control at end of turn. If you lose the flip, sacrifice it."

Sinew Sliver

All Slivers get +1/+1.

Urborg, Tomb of Yawgmoth

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

Homing Sliver

Each Sliver card in each player's hand has slivercycling {3}. Slivercycling {3} ({3}, Discard this card: Search your library for a Sliver card, reveal it, and put it into your hand. Then shuffle your library.)

Necrotic Sliver

All Slivers have "{3}, Sacrifice this permanent: Destroy target permanent."

Mutavault

{T}: Add {1} to your mana pool. {1}: Mutavault becomes a 2/2 creature with all creature types until end of turn. It's still a land.

Dismember

({B/P} can be paid with either {B} or 2 life.) Target creature gets -5/-5 until end of turn.

Gemhide Sliver

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

Harmonic Sliver

All Slivers have "When this creature comes into play, destroy target artifact or enchantment."

Mindlash Sliver

All Slivers have "{1}, Sacrifice this creature: Each player discards a card."

Psionic Sliver

All Slivers have "{T}: This creature deals 2 damage to target creature or player and 3 damage to itself."

Screeching Sliver

All Slivers have "{T}: Target player puts the top card of his or her library into his or her graveyard."

Sedge Sliver

All Slivers have "This creature gets +1/+1 as long as you control a Swamp" and "{B}: Regenerate this creature."

Telekinetic Sliver

All Slivers have "{T}: Tap target permanent."

Overgrown Tomb

Verdant Catacombs

Chameleon Colossus

Breeding Pool

({T}: Add {G} or {U}.) As Breeding Pool enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Swamp

({T}: Add {B}.)

Forest

({T}: Add {G}.)