ScreenCastify is a good extension to easily record your screen. It will record the activity of your screen along with audio.
ScreenCastify Tutorial
To get an add-on you will need to get to "Add-on" and then "Get add-ons".
This add-on created awesome 3D charts, graphs and more. It adds bold colors and multidimensional to the chart or graph.
This add-on allows you to plot your data on a map. If you have a list of addresses in a Sheet, this add-on will map it on Google Maps.
This add-on converts any Google Sheet into a Google Doc.
