I still use the Little Rat extension, it shows a little notification when an extension does a network request, and lets you see quickly what type and where. It can also block requests (doesn't seem to work all the time in Brave now, even with the flag on), activate and deactivate extensions:

https://github.com/dnakov/little-rat

There's also this site that I've used from time to time to audit extensions quickly:

https://chrome-stats.com/