Examples of an acid salt?

Acid salt' is a term for a class of salts formed by the partial neutralization of diprotic or polyprotic acids. Because the parent acid is only partially neutralized, one or more replaceable hydrogen atoms remain. Well known examples are sodium hydrogencarbonate (NaHCO₃), sodium hydrosulfide (NaHS), sodium hydrogensulfate (NaHSO₄), monosodium phosphate (NaH₂PO₄), and disodium phosphate (Na₂HPO₄).

The term 'acid salts' do NOT mean that their aqueous solutions are acidic.
For example, NaHCO₃ is an acid salt, but its aqueous solution is slightly alkaline.
One more example, NH₄Cl is NOT an acid salt, but its aqueous solution is acidic.

NH4Cl ( Ammonium chloride ) -- Salt of Weak Base & Strong Acid
NaH2PO4 ( Sodium dihydrogenphosphate )