Ordinary stellar interiors are plasmas in which all of the atoms we know are largely stripped of their electrons in the deep interior of the star. In the surface regions where the temperatures range from 50,000 to as low as 2000 K depending on the type of star ( O-type vs M-type) some of the atoms have regained most of their compliment of electrons, but the gas is still a plasma with an ionization fraction above 50 percent.
White dwarfs are degenerate matter in a solid state. They have a density of millions of grams per cubic centimeter and are often helium or oxygen-rich. The nuclei are frozen into a quantum solid even though the temperature of the matter can be over 100,000 K to start with. They cool over billions of years to much lower temperatures. There is no nuclear fusion occurring in these stellar cinders. The electrons, however, are not bound to the nuclei so the matter is a 'solid plasma' . The electrons behave like a peculiar gas within the nuclear quantum solid, and it is the 'degeneracy pressure' produced by these electrons that supports the star against gravity.
Neutron stars are even denser at 100 trillion grams per cubic centimeter. The nuclei have completely dissolved in the interior, though in a thin shell a few meters thick at the outer surface there may still be conventional nuclei present though perhaps in exotic isotopic forms that are very neutron-rich. In the deep interior, the protons and electrons have combined to form neutrons, and the neutron star is about 95 percent or more pure neutrons. The traces of protons and electrons that were not 'neutronized' once again exist on the surface of the neutron star. The state of this matter is sometimes referred to as a quantum crystal.