Do a search on My Oracle Support. Search by product for Oracle Application Access Controls Governor (AACG), and you should find that the original distributable or the 8.5.1 release should have the content bundled with it. You can also open a ticket to get the exact version for your OS.
The best practice library files will be available in the directory you have downloaded and unzipped the GRC media pack from edelivery. Go to the specific directory in the system / server and select "Content" folder. You can copy the files on to your desktop and upload the same into AACG.
Hope this helps. Let me know if you need any further assistance.