Have you been to the PTCB website? If not, it's www.ptcb.org, and they should have some helpful information.
Also, I'm a member of the NPTA, and here is a section of their website that lists study books for the certification exam (http://www.pharmacytechnician.org/en/catalogs/). Hope this helps!!🙂
The PTCB has a video/workbook review series. I used that to prep for the exam. I found it pretty helpful, although I should have spent more time on it.