TreeSize - TreeSize tells you where precious disk space has gone to.
DiskBoss - A file manager with a focus on storage side of things: Monitoring, classing, storage, duplicate...
Baobab - Distributor of workload automation, financial statement reporting, data access, IT Asset Management and Service Desk software solutions.
DiskWave - DiskWave is a free utility to help you determine where most of your hard drive space is consumed.
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.
DiskSavvy - DiskSavvy is a free, fast and easy-to-use disk space analyzer utility allowing one to analyze disk...