TechTool Pro - Techtool Pro is a robust hardware diagnostic tool available for Macintosh.
AVG PC TuneUp - Peak performance for your PC. Keeps it going for longer. - More Speed Turbo Mode
DiskWarrior - DiskWarrior, the world's most advanced and highest rated hard disk, hard drive, and disk repair and data recovery tool for macOS, OS X and Mac OS X.
BleachBit - When your computer is getting full, BleachBit quickly frees disk space.
Disk Drill by Cleverfiles - Recover any type of deleted files in Windows & Mac including Office documents, messages, and media files quickly and easily.
CCleaner - CCleaner cleans, speeds up and frees up space on business endpoints.