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.

Thalia, Guardian of Thraben

First strike Noncreature spells cost {1} more to cast.

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.

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.)

Striking Sliver

Sliver creatures you control have first strike. (They deal combat damage before creatures without first strike.)

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.

Venom Sliver

Sliver creatures you control have deathtouch. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it.)

Phyrexian Revoker

As Phyrexian Revoker enters the battlefield, name a nonland card. Activated abilities of sources with the chosen name can't be activated.

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.

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.

Nihil Spellbomb

{T}, Sacrifice Nihil Spellbomb: Exile all cards from target player's graveyard. When Nihil Spellbomb is put into a graveyard from the battlefield, you may pay {B}. If you do, draw a card.

Thassa, God of the Sea

Indestructible As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.) At the beginning of your upkeep, scry 1. {1}{U}: Target creature you control can't be blocked this 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."

Sedge Sliver

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

Overgrown Tomb

Verdant Catacombs

Fatal Push

Blood Crypt

({T}: Add {B} or {R}.) As Blood Crypt enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

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.

Godless Shrine

({T}: Add {W} or {B}.) As Godless Shrine 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}.)