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.
2captcha - 2captcha is captcha bypassing software which offers various exciting tools and simple module that gives the fundamental outlook of the captcha.
reCAPTCHA - reCAPTCHA is a free security service that protects your websites from spam and abuse.
CAPTCHAs.IO - One of the most stable and fast yet affordable captcha solver API web service provider online.
AuthKong - A reliable captcha service, offers advanced security to protect websites from spam and abuse while ensuring a user-friendly experience for legitimate visitors.
Captcha Sniper - The only captcha solving solution you will ever need. Period.