This one comes up in the "More Like This" link in the community
BaneBot stuff is used all the time.
Vexpro is definitely a good one to have.
Standard sizes of SAE and Metric hardware
Sprockets (Martin Sprocket, McMaster Carr, http://www.sdp-si.com/)
#1 however, is a PTC managed Windchill Library Image may be NSFW.
Clik here to view.
Also, assuming a PTC-managed library, association to spec. sheets would be good too.