Clot Sliver

All Slivers have "{2}: Regenerate this permanent."

Plains

Sliver Legion

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

Mistgate Pathway

Hengegate Pathway

Hengegate Pathway // Mistgate Pathway

Planar Bridge

{8}, {T}: Search your library for a permanent card, put it onto the battlefield, then shuffle.

Island

Sliver Overlord

{3}: Search your library for a Sliver card, reveal that card, put it into your hand, then shuffle.
{3}: Gain control of target Sliver. (This effect lasts indefinitely.)

Fabricate

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Crystalline Sliver

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

Cloudshredder Sliver

Sliver creatures you control have flying and haste.

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters, you may pay 2 life. If you don't, it enters tapped.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Sliver Queen

{2}: Create a 1/1 colorless Sliver creature token.

Basalt Monolith

Basalt Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap Basalt Monolith.

Rings of Brighthearth

Whenever you activate an ability, if it isn't a mana ability, you may pay {2}. If you do, copy that ability. You may choose new targets for the copy.

Gemstone Array

{2}: Put a charge counter on Gemstone Array.
Remove a charge counter from Gemstone Array: Add one mana of any color.