DISKINFO by Gaby Chaudry serves primarily to analyze floppy disks of unknown formats. If you have a bunch of unkown diskettes with unkown formats you are able to get a fast info about them with DISKINFO. The program is effective and easy to use. Must have!
This program also recognizes foreign formats such as CP/M!
The last entry on her news page is from 2012 but the site is still online. If you are looking for CP/M, Z80, S100, ..., Gabys website is good entry point.
Another very good program is DI (Diskinfo) - Version 4.50 - by Peter Norton. More detailed, just good. This program can only handle DOS floppy disks, no foreign formats!