You can scan and preview any number of files. However, when you attempt to save them, the program triggers a 5-second delay for every single file and requires you to click "Continue unregistered" manually.
The "free" experience is essentially a trial with full functionality but intentional delays: diskdigger license key updated free
Disk Digger v1.67.37.3271 - The Portable Freeware Collection You can scan and preview any number of files