ChimpMate is a MailChimp based email marketing plugin. Professional and Custom designs. Includes Lightbox, Slider, Widget, Add-on, Topbar and Flipbox
The free and easiest way to increase your email subscribers by over 500%. MailMunch lets you create beautiful optin forms for your WordPress.
Drag and Drop interface. Tens of predefined fields, including Connect with Facebook and Google+. 37 languages. Responsive design. Double opt-in.
Single Opt-In AJAX Mailchimp Newsletter form for WordPress. You can switch between single opt-in and double opt-in. Use it as Widget or Shortcode.