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

htop - htop - an interactive process viewer for Unix. This is htop, an interactive process viewer for Unix systems. It is a text-mode application (for console or X terminals) and requires ncurses. Latest release: htop 2.

DaisyDisk - DaisyDisk is a disk analyzer tool for OS X that visualizes hard disk usage and allows to free up hard disk space.

Tron Script - Tron is a glorified collection of batch files that automate the process of cleaning up Windows systems.

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.

Stats - Simple macOS system monitor in your menu bar.