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.
Really Good Emails - A large collection of good product email design.
reCAPTCHA - reCAPTCHA is a free security service that protects your websites from spam and abuse.
Email Inspire - Discover the best of email design and marketing — Browse email newsletters from top brands.
AuthKong - A reliable captcha service, offers advanced security to protect websites from spam and abuse while ensuring a user-friendly experience for legitimate visitors.
Good Email Copy - Email copy from great companies.