using tools such as epieos you can find out information such as the name associated to the account and the websites you have signed up on you can check breachdirectory to see if your email has been in any breached databases you can also find plenty of websites to help you find more info such as osintframework
If you're talking about your own personal mail, just think about every single service you have shared your address and name, all of that info can be potentially used to track you.