hCaptcha - Do you use a captcha to keep out bots? hCaptcha is a drop-in replacement for reCAPTCHA that earns website owners money and helps companies get their data labeled.
Splashy - Breathtaking, auto changing wallpaper app for macOS, Windows, Linux, iOS & Android
MTcaptcha - Enterprise Captcha solutions
Wallcat - Enjoy a new, beautiful wallpaper, every day.
GeeTest CAPTCHA - GeeTest protects your websites, mobile Apps and APIs from bot threats.
Variety Wallpaper Changer - Variety is a wallpaper changer for Ubuntu which is featureful, yet slim and very easy to use.