Good on you for acknowledging that is a problem and moving to fix it. The existing list makes a lot more sense now that I know it is just the top 500 sites.

I think you generally want to stick to sites that are both public and consumption oriented. News sites and places like Wikipedia are the obvious examples. Social media is a little more questionable since there is a mix of public and private data. I think an ideal system would break sites out into categories like news, education, pop culture, social media, etc. You then allow the users to either turn off a category as a whole or provide an advanced mode to manually disable individual sites. Although it has been a while since I messed with browser extension permissions so I don't remember if these permissions can even be set on a conditional basis. Either way, there can always be an option in the extension settings to ignore those pages even if the browser technically gives you permissions to them.