Manufacturers are coming along with content but I still have to make my own from time to time. I bring a PDF into AutoCAD then trace out the design then bring the AutoCAD tracing into Revit to trace it again to make the family. I would like to be able to bring the PDF into Revit MEP so I can trace or pick lines instead and bypass AutoCAD.
I wouldn't trust a pdf to be drawn well enough.
Also I always size my families using parameters & reference planes, so I can draw the geometry any old size, then align-lock it to the reference planes.
Those two statements are completely contradictory... oh well...