MailStore - MailStore Home - A 100% free single-private-user desktop solution
SysTools Outlook PST Converter - Convert PST to EML File Format, as well as Extract Emails from Outlook Files & Folders to TXT, RTF, MHT & HTML by Outlook PST Converter Tool for Mac & Windows by Systools
Gmvault - Backup the emails in your Gmail account.
ToolstoExport PST Exporter - PST Exporter – Move Outlook PST Data File to MBOX, PDF, MSG, EML, EMLX, VCF and ICS
Mail Backup X - Your one stop mail backup and archiving tool for Mac.
ReliefJet Essentials for Outlook - A large set of useful and easy-to-use tools for every Microsoft Outlook user: Import, export and convert using EML,MSG,TXT and PST formats; remove duplicate items, process attachments and extract addresses; get reports and statistics and even more...