Large sheets of various plastics

There are plastics shop near Taipei main station near Taiyuan road.

I’m looking for large sheets of various plastics for vacuum forming. The stuff they sell in hobby shops is too small and too expensive. I’m hoping for polystyrene, polycarbonate, abs, and even interesting colored or textured stuff.

Also, if anyone knows where to get Delrin® acetal resin (a dark plastic that can be machined) and used to make hard wearing items such as knife handles, RC car chassis, wheels, and other stuff, please let me know.