Calendly is an app for scheduling appointments, meetings, and events.
Clutch review widgets are stand-alone applications that you can embed on your website to show your dynamic ratings and reviews.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
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.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Tilda is a web design tool.