Remo Duplicate File Remover - Remo Duplicate File Remover is a simple yet powerful duplicate file remover app that lets you easily search and remove duplicate files on your Android mobile and tablet.
WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
Files by Google - A file management app that helps you free up space, find files faster, share files offline, and back up files to the cloud.
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.
Dupdrop - Dupdrop – Duplicate File Remover is an Android tool created and published by Alexander Brunner.
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.