DriveDx is described as 'dvanced drive health diagnostic and monitoring utility. Unlike most drive utilities, DriveDx does not only monitor the drive’s built-in S.M.A.R.T' and is an app in the OS & Utilities category. There are more than 25 alternatives to DriveDx for a variety of platforms, including Mac, Windows, Linux, BSD and MS-DOS. The best alternative is CrystalDiskInfo, which is both free and Open Source. Other great apps like DriveDx are GSmartControl (Free, Open Source), HD Tune (Freemium), Hard Disk Sentinel (Paid) and Victoria (Free).
DiskWarrior is the safest, most technologically advanced, most powerful utility to eliminate directory damage and recover your files, folders and documents. DiskWarrior is so advanced it can even recover your data from a failing hard drive.
ZetaWatch is a small OS X program that displays the zfs status in the menu bar, similar to what iStat Menus does for other information. It is fairly well tested, but due to the current state of libzfs and libzfs_core, changes will be required until the API stabilizes.
This is a Windows version of the Data LifeGuard Diagnostics. It will test WD internal and external drives. In additional, it can provide you with the model and serial of WD drives attached to the system.