cdnjs is a free distributed JS library delivery service.
Google Hosted Libraries is a stable, reliable, high-speed, globally available content distribution network for the most popular, open-source JavaScript libraries.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
MailerLite is an email marketing tool and website builder for businesses of all shapes and sizes.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Showit is a drag-and-drop, no-code website builder for photographers and creative professionals.