This is a picture of the array of tools I keep on hand when building with Plastic Card. It is a assortment of clippers, generally I get a new set every years or so the best one I have so far is GallForce9's Large set. But to be honest the set from Harbor Freight are almost as good and half the price. The newest one from GW is sub-par, it works well but the bevel on the cutting face is a little steep, making tight or plunge cuts difficult and they are expensive.
A leather punch for making small circles not so good for making holes as bevel on each die tends to deforme the parent sheet.
A couple of Pin-vises with a variety of bits, Dremel make a nice Index of bits, 7 bits with the largest being 1/8th inch.
A carbide tipped scribe, good for marking up and detailed scribing and cutting they are generally $5 or $6 in the hardware store, look with the rest of the marking and measuring tools.
A selection of flat faced pliers and hemostats, these are very useful for holding onto little bits when scribing a break point.
Other tools not pictured. well mostly, files and rasps, sanding blocks pre-made foam/sponge core and older "wrap sand paper around" types. these are use to.... Need I explain? Wait, the softer sponge core one are great for rounding complex curves as they tend to follow the surface better than sand paper around the finger.
Ok, these are the basics of the tools I commonly use when building with plastic card and sheet. I use a different subset when working with putty, mostly the addition of wax and dental tools generally sold as sculpting tools, a variety of wooden pottery tools and set of Clay Shapers, brush shaped tools with a number of differently shaped silicon tips.
