We have a Suitelet loading a HTML table, but want to see what else can be done graphically. Anyone integration with Grafana and similar - to display charts and tables?

You can use pretty much any js library to build stuff and throw it into an html field.

Or you can build suitelets completely with HTML (i.e. no N/ui stuff at all)

For charting, I would personally just use highcharts since its well documented and easy to get started.