Clot Sliver

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

Essence Sliver

Whenever a Sliver deals damage, its controller gains that much life.

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

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

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

Sliver creatures you control have flying and haste.

Slivers can't be blocked except by Slivers.

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