The free AutoCAD blocks that you download are in a zip file. Once you have downloaded the free CAD symbols, you can unzip the file to any location on your hard drive. All the blocks are in one AutoCAD drawing file called '2007 ArchBlocks Free Download.dwg'. The file is compatible back to the AutoCAD 2000 version.

Autocad Furniture Library

Solution:

AutoCAD and AutoCAD LT have a limited set of symbols which are available on the sample tool palettes. One can find an icon on the Ribbon panel -> View tab -> Palettes panel, to launch the palettes. Alternatively, one can use the keyboard combination CTRL+3 to access the same palettes. That said, that is the sum of the symbology available within the application.

Some symbols can be found in the sample files that come with AutoCAD. These are located:
C:Program FilesAutodeskAutoCAD 20xxSampleen-us
There are however other resources available for block libraries, the following are just a handful found using a Google search:

Autocad Furniture Library Free Download