I created a few nice looking websites with the free version of RocketCake - it it very easy to use and simply gets out of the way. It has all the options I need and you can create complicated stuff with mostly a few clicks.
Webflow - Build dynamic, responsive websites in your browser. Launch with a click. Or export your squeaky-clean code to host wherever you'd like. Discover the professional website builder made for designers.
D3.js - D3.js is a JavaScript library for manipulating documents based on data. D3 helps you bring data to life using HTML, SVG, and CSS.
WiX - Create a free website with Wix.com. Customize with Wix' website builder, no coding skills needed. Choose a design, begin customizing and be online today
Chart.js - Easy, object oriented client side graphs for designers and developers.
Grapedrop - Build free, responsive, website pages with an easy to use online builder. Design and publish online immediately or export the code and host it wherever you want
Google Charts - Interactive charts for browsers and mobile devices.