What is an example of a polyatomic ion?

$N {O}_{3}^{-}$, $C {O}_{3}^{2 -}$, $P {O}_{4}^{3 -}$, $S {O}_{4}^{2 -}$, $N {O}_{2}^{-}$, ${S}_{2} {O}_{3}^{2 -}$, $C l {O}_{4}^{-}$. Do I win 5 pounds? In all of these examples the negative charge(s) formally lies on the oxygen atom - i.e. it lies on the most electronegative atom.