My employer has several dozen domains that were registered by a previous marketing team, who felt they needed to register every possible variant/misspelling they could think of. The vast majority of them simply redirect to our main domain, which has now been in use for ten years (long enough to be well-established).
I am of the opinion that it isn't worth the investment to keep renewing all these domains – but I'm reluctant to let them go, because I'm sure squatters will buy up many of them and add them to their abysmal ad networks, and perhaps impact the SEO for our real domain. (Fortunately a lot of them don't use our current brand name, but many do.)
How should we decide which ones to keep? Is there a way to use Google Analytics (which I'm less familiar with than I'd like) or other tools to see which, if any, are actually being visited and might have any value, to us or anyone else? (I have searched each one in Google (e.g.
site:blahblah.com) and 90% of them have not been indexed since they have never been linked anywhere nor hosted any content.)