According to Google Support you can use the recovery link on this page: Recovering sign-in information
From here, you should try with all accounts you are associated with to see what accounts are linked. (Assuming you remember all email accounts used apart from the one you forgot). It is sort of hit and miss but it has worked for me on two separate occasions.
You should get an email similar to the following.
Your recovery address, phwd@gmail.com, is associated with:
xxxx@gmail.com
xxxx@gmail.com
xxxx@gmail.com
xxxx@gmail.com
xxxx@gmail.com
To sign in, visit the link below.
http://www.google.com/accounts/
If you've received this mail in error, it's likely that another user
entered your email address by mistake while trying to recall their
username. If you didn't initiate the request, you don't need to take
any further action and can safely disregard this email.
If clicking the link above does not work, copy and paste the URL in a
new browser window instead.
Thank you for using Google.
For questions or concerns regarding your account, please visit the
Google Accounts FAQ at http://www.google.com/support/accounts/.
This is a post-only mailing. Replies to this message are not
monitored or answered.
As seen above it works for multiple accounts. So any account that has phwd@gmail.com listed is brought up in the list.
Additionally you can search your email accounts for the following subject line
Your Gmail address has been created
This will bring up (if you didn't delete it), the confirmation email messages of all Gmail accounts you used the current account as a recovery point. Although, based on "used in ages" I am not sure how far back Google used to send out this message.
It is not possible to recover an account without a government issued ID. You can recover your account using your email account. If you don't have access to your email and phone number you need to provide a government issued ID at any cost to verify that it belongs to you legally. From my personal experience, I provided government issued ID but I was not able to recover my account after that.
Best Answer
I have forgotten my password, but my browser remembers it
If your browser remembers your password (that is, the password field is automatically populated when you log in to your Google account, and you're able to log in), you should be able to retrieve your password through your browser's password manager.
See the instructions for your browser:
I have forgotten the password for my private Google (Gmail) account
I have forgotten the username / email address for my private Google (Gmail) account
In order to recover your Google username using this form, you must already have specified a recovery email address or recovery phone number.
If you haven't specified any recovery information, you may still be able to find your username if you have fairly recently accessed your email account through a browser. Gmail displays your email address in the browser's title bar, so searching your browser's history for
Inbox
orGmail
might reveal your email address.I have forgotten the username / email address / password for my work Google account (Google Workspace)
If you have an account on the Google Workspace service, you may still use the method described above. If this proves unfruitful, contact the administrator for your domain, who will be able to reset your password and/or find your username.
I have forgotten the admin username / email address for a Google Workspace account that I manage
First, try the methods described above. If this is unsuccessful, you may still reset the admin password by domain verification.
I have forgotten my username / email address / password, but I have a desktop / smartphone email client that still can fetch mail from my account
If you have already set up an email client to fetch mail from your account, you might be able to extract the username / password from that client.
Instructions on how to do that will vary depending on which client you use. Here are links to instructions for some of the most common clients:
I have no access to my recovery email, phone, or any other option
You may still be able to restore access to your account by manually verifying your identity.
You will then be asked a series of questions which you must answer to the best of your ability. If you can provide enough accurate information, you will get your account back.
How do I prevent losing access to my account in the future?
See How do I protect my Google/Gmail account?