Insulator
Electrical insulation is not the absence of a property but the presence of one — a band gap wide enough that no electrons are available to carry current at ordinary temperatures. What distinguishes the materials here is what else they have to survive: heat, ultraviolet light, moisture, mechanical load and, above all, the electric field itself.
Breakdown is the failure that matters, and it is a field strength rather than a voltage. Every insulator has a limit above which it conducts catastrophically and usually permanently, which is why high-voltage insulation is about shape and thickness as much as about material.
Compound
Aluminium oxide
Industrial alumina — the refined intermediate between bauxite and aluminium metal, and a major ceramic in its own right.
Material
Amber
and historically the important one: rubbed amber holds a static charge well enough that the effect was named after it
Material
Asbestos
thermally and electrically, and fireproof, which is the combination that made it ubiquitous
Material
Bone china
and it is a better dielectric than hard-paste porcelain, though the electrical trade stayed with porcelain on cost
Material
Ferrite
electrically, while carrying a magnetic field — a combination no metal offers, and the entire basis of high-frequency magnetics
Material
Mineral wool
thermally and acoustically, which are the same property here — a fibrous mass that stops convection also absorbs sound
Material
Optical fibre
electrically, which is why fibre is used where lightning, ground loops or explosive atmospheres rule copper out
Material
Polyethylene
The most-produced plastic in the world — a chain of carbon and hydrogen, whose properties depend almost entirely on how the chains are branched.
Material
Polystyrene
thermally, as expanded foam — one of the cheapest ways to insulate a building there is
Material
Polytetrafluoroethylene
electrically as well as thermally, and one of the best dielectrics available for high-frequency cable
Material
Technical ceramic
Engineered inorganic non-metallic materials — hard, heat-resistant, chemically inert, and brittle in a way that governs how they are used.
Each of these uses is established and cited on its own. Whether something counts as an ore, for instance, depends on grade, price and era — and those qualifications are shown alongside it.