MailStore - MailStore Home - A 100% free single-private-user desktop solution
Gmvault - Backup the emails in your Gmail account.
SysTools Gmail Backup - Backup Gmail Emails, Contacts, Calendar, and Google Drive Storage File by SysTools Gmail Backup Solution
Mail Backup X - Your one stop mail backup and archiving tool for Mac.
imapsync - Console-based utility for migrating IMAP mailboxes.
UpSafe Gmail Backup - Upsafe Backup. Affordable corporate G suite backup Office 365 backup. Keep your mail and documents safe - sign up for free now!