In theory, any professional who renders services upon which you and others rely upon can commit malpractice. Often, the professional is licensed or regulated by the state.
Accountants, attorneys, actuaries, chiropractors, dentists, physicians, psychologists and therapists are typically the persons named in a "malpractice action". When others engage in malpractice, the action usually not specifically called malpractice, but negligence. In actual practice, only those who hold themselves out as having special skills or abilities are held accountable in malpractice litigation.