WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.

HD Tune - HD Tune Pro is a hard disk / SSD utility with many functions. It can be used to measure the drive's performance, scan for errors, check the health status (S. M. A. R.

WizTree - WizTree quickly finds the files and folders using the most space on your hard drive. It scans the MFT (Master File Table) instead of crawling the entire disk which makes it very fast.

FakeFlashTest - Tests USB Flash drives and Flash memory SD cards to determine if they are fake (not full capacity).

SpaceSniffer - SpaceSniffer is a freeWare (donations are welcome) and portable tool application that lets you understand how folders and files are structured on your disks.

DRevitalize - Main objective of DRevitalize is to diagnose and repair magnetic media