Gmail doesn't offer this capability for now, however, there are a few ways to go about it. First, consider using a third-party tool, such as Sendinblue or Mailchimp, which allows for bulk emails to be sent from your Gmail account. Another option is to create a Google Group and add the recipient email addresses to it, then send the email to the group. This method allows for up to 2,000 recipients per email, so you'll need to send it five times to reach your 10,000 mark.