If you forgot your username, you can search for the titles of projects you shared, forum topics and studios you created, or projects you commented on, and see if you can recover it from there. If you email the Scratch Team from the address you signed up with, they may be able to find your username. You can also go to the password reset page and enter the email address you registered with, and your username will be emailed to you.
If you have multiple accounts with the same email address, all usernames and passwords associated with the email address will be sent in one email.
