There are plenty of materials that are "magnetic" and non conductive. Typically ferrimagnetic materials like YIG or other spinell containing Fe/ Co or Ni are very often "magnetic", but electrical insulators.
There are no so great number of good insulators and ferromagnetic (or ferrimagnetic) ones. Let me to tell you some of them.
The maghemite Fe2O3 is a semiconductor (band gap 2 eV) and no a metal, the same for nickel oxide NiO which has a band gap of 1 eV for the Ni 3d-band or for the compound Fe2O3-alpha-NiO being Fe and Ni metallic ferromagnetic compounds Another interesting magnetic compound is the YIG (Y3Fe5O12).which is a ferrimagnetic insulator for the electric charge and a good conductor for the wave-spin transport.