ncdu - A disk usage analyzer with an ncurses interface, aimed to be run on a remote server where you...
Baobab Disk Usage Analyzer - Baobab Disk Usage Analyzer is one of the light-weight disk analyzers that offers you a chance to view and monitor the disk usage & folder structure without any hassle.
K4DirStat - K4DirStat is the successor of former KDirStat.
WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
Filelight - Filelight is an application to visualize the disk usage on your computer.
MindGems Folder Size - Folder Size - Freeware file size analysis. Folder Size - is a freeware disk size analysis tool that will display the directory sizes and folder tree sizes on your computer including their subfolders.