Here are some great examples of D3 inside of Qlik Sense:

http://sense.axisgroup.com/sense/app/1dadc9e8-d2f5-47f8-ad21-a2209257cc20/sheet/xtcwya/state/analysis

This is the github repository:

https://github.com/skokenes/Qlik-Sense-D3-Visualization-Library

This is the Qlik Branch project page:

http://branch.qlik.com/projects/showthread.php?389-D3-Visualization-Library

Worth taking a look whenever you need a new way to visualise some existing data.