At higher densities, corrections to it are given by the virial expansion.
The Soave equation modifies it with the addition of an acentric factor, which is also included in another modification, the Peng-Robinson equation. Another modification was proposed by the scientist who proposed an explanation for the critical point as well as stating the law of corresponding states.  At higher densities, corrections to it are given by the virial expansion. Another correction is the Redlich-Kwong equation, which includes a term proportional to the inverse one half power of the temperature. High temperature, low pressure situations give the best agreements with the predictions of this equation, which implicitly contains Avogadro's law.  Derived from Charles' law and Boyle's law, FTP name this simple equation of state, typically given as PV equals RT.
The Soave equation modifies it with the addition of an acentric factor, which is also included in another modification, the Peng-Robinson equation.
the Ideal Gas Law (accept Redlich-Kwong before "Peng-Robinson", or van der Waals before "critical point")