Look at your router logs for your home. Most will show you which sites you are sending data too. It’s always googleads and facebook. I don’t have Facebook but every site that still supports them sends them data.

Edit: Pihole and Disconnect are good options for limiting what is shared. You have to dig into disconnect’s settings to completely shut off Google and Facebook. They warn you “you might get weird advertisements” but it’s better than being tracked on every site.