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

CleanMyMac X - Clean, protect and speed up your Mac

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.

MacKeeper - The new MacKeeper app delivers multilayered protection from malware, online threats, and identity theft & Mac performance optimization. Learn what is MacKeeper.

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.

Ambeteco MyQuickMac Neo - MyQuickMac Neo organizes, optimizes, speeds up, declutters, cleans, and cares about your Mac, fully automatically, using innovative algorithms and Artificial Intelligence to deeply analyze and optimize macOS from its core.