Of course you don't have to pick a filament type, but most folks prefer
to handle one type of material over another. Most of the library is in
PLA, but there are lots of different filament types represented!
Sometimes a manufacturer may have a certain color filament in multiple
formats, like ABS, PETG, and / or PLA. In that case, all of the versions
that I have are added. There is very rarely any color variance between
the different plastics, but that's for you to decide.
Each filament type includes all of its most common sub-types; for
example, the PLA category includes PLA+, Pro PLA, HTPLA, and more! If you
want to search just a specific subtype, use the filter bar at the top of
the screen.