All Sliver creatures have "This creature gets +1/+1 as long as you control a Swamp."

All Slivers have ": Regenerate this permanent." (The next time it would be destroyed, instead tap it, remove it from combat, and heal all damage on it.)

Menace

Ward—Pay 3 life. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays 3 life.)

Magecraft — Whenever you cast or copy an instant or sorcery spell, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."