I have noticed that NetHogs reports constant non-stop relatively large network traffic (send and receive) for the Brave Browser, even when I have only one static page (i.e. google search) open in my browser. This is the program displayed in NetHogs.
Could look at ≡ -> More Tools -> Task Manager and view the Network tab, to see what tab is using traffic. Making a new profile might be a good start also.
Thank you @fanboynz I am on Linux, and using NetHogs one has the ability to see which App is creating the traffic. I have uninstalled and re-installed Brave, and although the traffic appears to have gone down somewhat, it is still sending and receiving a non-negligible amount of data.