The material for the FFF process is generally called filament. Meanwhile, many plastics are available in any colors from a variety of manufacturers. It is wound onto a spool in wire form and can be unwound and printed directly from the spool. Spools are available from 0.25 kg up to 10 kg depending on the material. In general, except for a few exotics, there are two different sizes in diameter. 1.75 mm and 2.85 mm have become established here with most manufacturers for 3D printers, with the smaller variant being used most frequently. The processability of the different materials ranges from simple (PLA) to heavy (PEI, PEEK), which also always sets requirements on the 3D printer. Not all materials available in filament form can be printed with every FFF printer. The requirements here are primarily directed at the temperature management in the printers. Nozzle, build room and bed temperature, as well as the cooling of the mechanics and electrics.
The pyramid above shows an extract from the available plastics. Almost all of these plastics are now available for the FFF process. In order to find the right plastic for a specific application, the relevant literature must be used.