UA Shuffle от dogwater

UA Shuffle gives you full control over your browser’s User-Agent header. Instantly switch to a random entry from your custom list, or choose a specific string for precision. Features include:

• Preloaded with a wide variety of User-Agents for popular browsers, OSes, and devices
• Easy popup interface for quick switching
• Full editing of your User-Agent list without needing to reload the extension
• Works automatically on startup, or only when you click the button — your choice
  Perfect for testing website compatibility, avoiding unwanted tracking, and disguising your digital fingerprint.