Cleaner One Pro is the best Mac cleaner that can optimize memory usage and speed up your Mac . With the minimalist and easy-to-use interface, you can visualize, manage and free up your storage space in just one click. Cleaner One Pro also provides some advanced features including start up manager, application manager and file shredder. Keep your Mac clean and automatically tune it up for the best performance.
CleanMyMac X - Clean, protect and speed up your Mac
WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
CCleaner - CCleaner cleans, speeds up and frees up space on business endpoints.
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.
Cybertron Privacy Eraser - 1-click browsing history deletion, PC optimization & more
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.