Glary Utilities - The No. 1 Free, Powerful and All-in-one utility for cleaning your PC
CCleaner - CCleaner cleans, speeds up and frees up space on business endpoints.
Wise Care 365 - Wise Care 365 is a bundle of important registry, disk, and other system utilities for your PC.
AVG PC TuneUp - Peak performance for your PC. Keeps it going for longer. - More Speed Turbo Mode
Advanced SystemCare - Free optimization software & registry cleaner for Windows 10, 8, 7, Vista and XP. Advanced SystemCare Free to speed up PC, clean registry and repair system in one click.
Clean Master - Some users swear by it, some call it a glorified snake oil that does more harm than good. That can be said about any snake oil, but what specific brand of snake oil can boast almost a billion downloads around the world?