Easy library to make charts and graphs

Link here.

Beautiful analysis and visualization tool

Link here.

A javascript library, Cytoscape.js for analysis and visualization

Link here.

50 Javascript libraries for charts and graphs

Link here.

Amazing graphs using rickshaw javascript plugin

Link here.
It provides a set of functionalities to display a graph.
But whatever it does, does it awesomely.
Oh, doesn't work on IE8 currently though.

Charts on mobile anyone?

Link here.

If you're looking for simple bar-pie-plot graphs for mobile, take a look at it. Comment if you find anything better. I'' be glad to know. :)