Top Alternatives to Onyx

CCleaner is a widely recognized and powerful utility for optimizing Windows systems. It offers a suite of tools to clean junk files, remove unnecessary data, fix registry issues, and manage startup programs, aiming to improve performance and privacy.

AVG PC TuneUp is a comprehensive suite of tools designed to optimize and maintain Windows computers. It offers a range of features to clean up junk files, fix registry errors, manage startup programs, defragment hard drives, and improve overall system performance and stability.

Click&Clean is a comprehensive browser extension and system utility designed to enhance online privacy and maintain system performance. It provides a suite of tools for cleaning browsing data, safeguarding sensitive information, and optimizing your computer.

Cocktail is a versatile macOS utility designed to maintain, enhance, and troubleshoot your Mac's performance. It offers a comprehensive suite of tools for cleaning, repairing, and optimizing system settings to ensure smooth and efficient operation.

Toolwiz Care was a comprehensive, free PC optimization suite designed to enhance system performance, fix issues, clean junk files, and provide various utilities for maintaining a healthy Windows environment. It aimed to offer a wide range of tools for users to manage their computers effectively.

jv16 PowerTools is a comprehensive utility suite for Windows, designed to clean, optimize, and maintain your computer's performance and privacy. It offers tools for system cleanup, registry maintenance, software uninstallation, duplicate file finding, and more, aiming to provide a faster, more secure, and stable computing environment.

TinkerTool is a comprehensive freeware application for macOS, providing access to hidden system preference settings not typically available through the standard System Settings interface, enabling users to customize their macOS experience.