The reason you don't find them is because it's just like writing software, everything is custom.
Exactly what are you searching for?
I have found open source icons in the past, but like any open source application, they were not free, there were limitations of use.
I once tried to satisfy a clients wish for cheap, bad, horrible, ugly clip art libraries. As we discussed the project, it quickly became, "I want them to have this and that and this and that..."
"And oh, you want them to really be custom" I said. "Ok, well, let's do this on an hourly basis then."
Project completed before it even began...v