Herein, three material approaches, for the fabrication of thermally conductive and yet electrically insulating parts via additive manufacturing (AM) technologies, are described. Samples are prepared from light-curable resins, sol–gel-hybrid polymers, and thermoplastic materials using thermally conductive particles as fillers. AM sample preparation is done using vat photo-polymerization and material extrusion with subsequent measurements of thermal conductivity and electrical insulation properties. The main goal herein in addition to material development is the demonstration of manufacturing applicability including usage properties. Use cases are heat sinks for power electronics, which have to be thermally conductive to spread the generated heat and electrically insulating to ensure general functionality and long-term operation.