ABS: Mostly for prototyping, used to make Legos but it is not as strong when 3D printed. Paint-able with automotive shellac. ($17 for 2.5 lbs on ebay: my filament shop)
Carbon fiber: Carbon fiber is very strong when bundled in a continuous strand. It is black in color and expensive. It is only printable in specific machines (Spool $80 p/50/cu/cm.)
Fiberglass: Only printable in certain machines (Spool $35 p/50/cu/cm.)
iglide: a very low friction material made by Iguss, is great for sliding on bars without abrasion.
Kevlar: used to make bullet proof vests. Yellow in color. (Spool $60 p/50/cu/cm.)
Laywoo-D3: 3D printable material that looks like wood, it is similar to trex decking with a wood and plastic mixture.
Nylon: Hard, and very good for final product parts. Can be dyed different colors, but it is very hard to print and is therefore generally used in a mix. (Spool $220 p/1,000/cu/cm.)
– Bridge Nylon: Used to print gears in the Airwolf 3D printers.
PET: Used for water bottles and carbonated drinks. Provides an excellent moisture barrier, even when printed.
PLA: Creates great looking parts, its often used as a support material and it is not very durable.
Poly carbonate: used to make bulletproof glass, it is very hard and strong but it is more brittle than Nylon.
TPE: Used for washers around bearings, flexible and durable.
TPU: a very soft printable material which can be used for padding.
Voxel 8: Conductive ink for 3D printers.