I had a couple of questions about the tool box in solidworks. First of I noticed some types of screws and bolts and bearings are missing. Are these downloadable are there updates to the tool box. And also the different systems have me a little bit confused. Which system is used the most. Ansi Inch, Ansi Metric, BSI, AS, DIN. sometimes assemblies will have a specific screw or thread I will have trouble finding it base on the annotation.
For additional parts try http://www.3dcontentcentral.com/
For bearings, try: http://www.skf.com/portal/skf/home/products?contentId=000392&lang=en
Metric thread standards are basically all the same. Some fastener standards may have more variety of diameter/ thread pitch and length combinations than others.
Often the model is identical whichever standard you pick. I'd consult your local supplier of fasteners and see which standard they use.
I use the ISO standard unless I have a reason not to.