SolarWinds Backup - Modern server backup software
MailArchiva - MailArchiva is an email archiving, email compliance, and e-Discovery enterprise server.
SysTools Google Apps Backup - Quickly backup all Google Apps emails to PST, EML, MBOX & EML with G Suite Backup software.
Vaultastic - Vaultastic’s on-demand SaaS platform provides Protection, Visibility & Control for your Critical Business Data with Agile Cloud Archival.
Spanning Backup for Office 365 - Spanning Backup for Office 365 allows your organization to protect its critical Office 365 Mail, Calendar, OneDrive and SharePoint data. Specifically designed for Microsoft Office 365, Spanning makes backup effortless and recovery click-simple.
MailVault - MailVault is a cloud-based IT software that archives and self-prunes based on user settings.