ONERECOVERY is the best data&photo recovery software for Windows PCs and Macs. It can recover over 1000 file types and bring your lost data back due to various situations like accidental deletion, formatting, virus attack and more...
WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
CleanMyMac X - Clean, protect and speed up your Mac
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.
DaisyDisk - DaisyDisk is a disk analyzer tool for OS X that visualizes hard disk usage and allows to free up hard disk space.
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.
Fossils - Find and clean out all your old unused files