Loader.io - Loader.io is a simple cloud-based load testing service
imapsync - Console-based utility for migrating IMAP mailboxes.
Loadium - Performance Testing & Load Testing Tool
Gmvault - Backup the emails in your Gmail account.
LoadFocus - Cloud Testing Infrastructure | Cloud Testing Services and Tools for Websites & APIs.
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.