Gemhide Sliver

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

Sol Ring

Sliver Queen

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

Manaweft Sliver

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

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

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.)

The First Sliver

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Sliver spells you cast have cascade.

Sliver Hivelord

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