Cryoserver - Cryoserver is an all-in-one email archiving solution that empowers you to preserve your email in a tamper-evident archive, making you transform your data into a useful archive for everyday use.

Bluetick.io - Personal touch at scale for all your follow-up emails

Gmvault - Backup the emails in your Gmail account.

FlowUp - AI-Enabled Omnichannel Automated Lead Follow-up System

imapsync - Console-based utility for migrating IMAP mailboxes.

Rebump - Automatic follow up emails. Keeps on bumping until you get a reply.