Splunk Stream (https://splunkbase.splunk.com/app/1809/), a free Splunk supported app/add-on, can collect Netflow data, but in terms of analysing specifically the Netflow data there are no built-in dashboards.
I have seen a number of different Netflow related dashboards made by customers to visualise the data.
The Stream app can do a lot of things not possible with Netflow on its own, and the app does have dashboards out of the box for some of that capability.
