DiskBoss - A file manager with a focus on storage side of things: Monitoring, classing, storage, duplicate...
DiskWave - DiskWave is a free utility to help you determine where most of your hard drive space is consumed.
DiskSavvy - DiskSavvy is a free, fast and easy-to-use disk space analyzer utility allowing one to analyze disk...
RidNacs - RidNacs is a very fast disk space usage analyzer for Microsoft Windows.
Duc - Duc is a collection of tools for inspecting and visualizing disk usage.
Disk Xray - Disk Xray is a disk usage statistics viewer, duplicate files and folders finder and cleanup tool for Mac OS X. Disk Xray performs three fundamental functions, and it performs them great.