I'm told that all the content that was on that site is available within the default Autodesk Fabrication configurations (CADmep, CAMduct, ESTmep). 

As Autodesk hasn't actively managed the content in a few years, I'd be cautious of using the content without verifying the dimensional accuracy. 

If you need custom content built and don't want to do it yourself, this company is one of the leading providers of custom content for Autodesk Fabrication. https://itembuilders.com/