Unfortunately, not all of us (not even all Ppruners) have the resources of NASA or Kroll!
There was some chap who had a blog or YouTube channel who worked in the HD recovery business and put up a few ideas for people who want to try DIY stuff. If I can find the link, I'll post it.
No substitute for the professional jobs, of course, but if you like fiddling, it might keep you occupied even if chances of success are minimal if you've no prior experience.
Aah.. here we go.... Mr Scott Moulton from the aptly named MyHardDriveDied.com. Various presentations to be had on his website.