One of the must-have tool to represent any dataset in a graphical or interactive manner.
This superb classified gallery of examples of many graphs, charts and diagrams demonstrates what can be made with the free D3 javascript framework.
Tip: click on the small top “D3” title to see even more examples, more than 500, but unclassified.
Usage experience: we use the D3 library on this website extensively. This is without any doubt one of the best library to convert data into nice and clear visualisation. One aspect to have in mind tough: it has been expanded and expended over the 10 last years for more possibilities, features browser compatibility, javascript compatibility and performance, but for graphs types existing since the beginning (ex.: tree), you will find online many examples done with the D3 v3 … that are not compatible with breaking changes introduced in v5, v7, but particularly in v6. So chose your starting point and online exemples wisely.