Privacy Badger is a Chrome and Firefox add-on which automatically blocks web trackers.
The AdBlock Plus-based tool doesn't use blacklists, instead monitoring the many sources which make up a typical web page, detecting and disabling servers which seem to be tracking you across multiple sites.
To reduce the chance of breaking a website, Privacy Badger will allow potentially important content - embedded maps, images, fonts - but still block the tracking cookies of offending domains.
And it uses Do Not Track, too, which should at least help with sites which honour DNT requests.
Privacy Badger adds an icon to the address bar, and this gives you immediate feedback on the current site. A green indicator means it's tracker free; yellow indicates there's a tracker, but it's necessary for the page, so only its cookies are blocked; red means a tracker had been blocked in full.
If you're unhappy with any of this - maybe a site just doesn't work any more, despite Privacy Badger's efforts - click the icon, and you'll find buttons to disable Privacy Badger for this site, or deactivate the add-on entirely.