DaisyDisk - DaisyDisk is a disk analyzer tool for OS X that visualizes hard disk usage and allows to free up hard disk space.
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.
CleanMyMac X - Clean, protect and speed up your Mac
ncdu - A disk usage analyzer with an ncurses interface, aimed to be run on a remote server where you...
MacFly Pro - Smart assistant for better Mac performance
WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.