http://www.seagate.com/www/en-us/support/downloads/seatools
http://support.wdc.com/product/download.asp?groupid=502&sid=30%E2%8C%A9=en
http://www.samsung.com/global/business/hdd/support/utilities/Support_Shdiag.html
http://www.fujitsu.com/us/services/computing/storage/hdd/support/utilities.html
http://www.hitachigst.com/hdd/support/download.htm
Toshiba - N/A
There are no tools available for Toshiba, but you may be able to use IBM or Maxtor's drive tools as well as other third party programs.
IBM is supported by Hitachi.