Xee3 - A better Mac OS X's Preview.app
WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
MacFly Pro - Smart assistant for better Mac performance
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.
Power Mode Switcher for macOS - macOS Monterey introduced a new feature for some Macs called Low Power Mode so you can save energy while keeping your Mac cool and quiet.
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.