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.
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' .