Shred is what I used when destroying a bunch of old drives.
Then I disassbled them to pull out the magnets and platters (because they're shiny and cool). A couple had torx screws that I didn't have the right end for so I ran a hdd magnet over the surface and scratched them with a screwdriver.
I use it multiple times a day. I only know basic usage, but it's super useful as part of an awk/grep/sort/uniq pipeline, basically just extracting a field to work on.