Acetal (Delrin, Celcon)
Acrylic (Lucite, Plexiglass)
Nylon
Nylatron
Polycarbonate (Lexan, Hyzod)
Polyethylene (UHME, HDPE)
Polypropylene
PVC
Styrene
Tefon

These materials can be produced in quantities from a one piece prototype to production quantities of thousands.