The gallery includes several examples adapted for use with r2d3 from https://github.com/d3/d3/wiki/Gallery. Other good sources of D3 examples are https://bl.ocks.org/mbostock and https://vida.io/explore.
To learn more about how to code your own D3 visualizations, check out the article on Learning D3.
