Did you know that you can find unused online accounts just by searching through your email?
Enter “confirm your email” into your email’s search box and you should be able to find lots of registration emails to online accounts, many of which you no longer use. Given recent security threats, it’s probably a good idea to delete these accounts if you don’t use them anymore.
If this search brings back a ton of Amazon order confirmations and you plan on keeping your Amazon account open, you can search for “confirm your email -Amazon” instead to exclude these from your results.
You can also hunt for newsletters you no longer care to receive by searching for “unsubscribe”.