Ancient Ziggurat

{T}: Add one mana of any color. Spend this mana only to cast a creature spell.

Predatory Sliver

Striking Sliver

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

Sliver Hive

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a Sliver spell.
{5}, {T}: Create a 1/1 colorless Sliver creature token. Activate only if you control a Sliver.

Sliver Legion

All Sliver creatures get +1/+1 for each other Sliver on the battlefield.

Cavern of Souls

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

Manaweft Sliver

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

Sinew Sliver

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Muscle Sliver

Crystalline Sliver

All Slivers have shroud. (They can't be the targets of spells or abilities.)

Phantasmal Image

You may have Phantasmal Image enter as a copy of any creature on the battlefield, except it's an Illusion in addition to its other types and it has "When this creature becomes the target of a spell or ability, sacrifice it."

Unclaimed Territory

As Unclaimed Territory enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Galerider Sliver

Sliver creatures you control have flying.

Gemhide Sliver

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

Heart Sliver

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.)