If it's hard to find - then probably it does not exist. I know before - many-many years ago (20 years) was companies on US market, that have been selling special libraries of materials, fills and objects. But I'm not sure they are still alive.
Maybe try to ask local distributors - if they know anything. This is one of their responsibilities - to provide ArchiCAD clients with additional solutions.
I never was satisfied with available libraries - so I started to collect information and built my own library of textures and building materials. So instead of using standard fills and materials available - I was downloading textures from supplier web-site, drawing symbol fills to represent let say timber or marble and entering physical parameters for building material.
I also been creating my custom library parts - by downloading 3D models from the manufacturer web - and converting it into library part. Converting models from Revit (using plug-in), 3ds max, 3D DWG and many others.
But, to achieve really good quality, GDL scripting needs to be involved and it's time consuming process.
Exist one big web-site, that trying to cover international market as wide as they can. Called BIM objects: bimobject.com
They have very big libraries of real product, but I never can find there what I want.
