This dashboard visualizes traffic acquisition data from Google Analytics. Apart from scorecards showing a break-up of traffic by each channel, there are donuts and bar graphs to show sessions by source for each channel.
Google Data Studio Template
This Google Data Studio Template visualizes Traffic Overview from Google Analytics. Page 1 of the report contains Traffic Overview which is ready to use with your own data source. Page 2 contains calculated fields in two of its charts i) Sessions by business region ii) Events/Session scorecard