Being involved with retro computers, I have a few floppy disks (of the 3.5-inch variety) that I would like to preserve as faithfully as possible. Of course, I know there are dedicated devices for doing that, such as the Kryoflux or the SuperCard Pro. But it occurred to me that I already own the required hardware to capture the low-level data from a floppy disk: my Saleae Logic 8 logic analyzer.
Another semi-automated way to capture raw (magnetic flux) disk images from floppy disks, this one using a drive and a logic analyzer with some post-processing. In addition to the other tools mentioned in the post, AppleSauce is a great option.