What is the strongest filament type?
PEEK may well be the strongest filament out there (and it has other interesting properties to recommend it), but it is very difficult to print and requires a printer designed to operate at high temperatures. If you are still using PLA, your next port of call should be PETG. It is a lot stronger than PLA (although it will shatter if hit hard enough) and it is almost as easy to print. It also gives off hardly any fumes and it can be printed without an enclosure.