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}.

Gemhide Sliver

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

Arcane Signet

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

Harmonic Sliver

All Slivers have "When this permanent enters, destroy target artifact or enchantment."

Spiteful Sliver

Sliver creatures you control have "Whenever this creature is dealt damage, it deals that much damage to target player or planeswalker."

Jodah, Archmage Eternal

Flying
You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells you cast.

Heart 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.)

Sol Ring

Cloudshredder Sliver

Sliver creatures you control have flying and haste.

Morophon, the Boundless

Changeling (This card is every creature type.)
As Morophon, the Boundless enters, choose a creature type.
Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.

Crystalline Sliver

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

Predatory Sliver

Sentinel Sliver

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