There are various kinds of plastic you might find yourself working with - make sure you know what it is!
This page is intended as a very rough overview, once we write down more information you'll find links to more detailed pages at the bottom.
More difficult to 3D print than PLA, potentially hazardous fumes - further reading anyway: RepRap wiki
Thermoplastic based on a byproduct from the paper industry
What most plastic bottles are made out of
Commonly used in 3D printing
Thermoplastic, easy to laser cut or bend under heat. Also known as "Plexiglass"