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...

Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.

PCVARE Thunderbird Converter - Try Thunderbird Converter to export from Thunderbird to Outlook PST, MSG, EML PDF, HTML, EMLX, RTF, MBX & MBOX. Thunderbird Converter can Migrate MBOX files from Thunderbird into MS Outlook, Outlook express, Windows Live mail, Mac Mail.

MailClark - The Slack bot for external communications

BitRecover MBOX Converter - Convert MBOX files of Thunderbird, Apple Mail, Eudora Mail, SeaMonkey, Google Takeout, etc. The tool offers 30+ output options like PST, EML, MBOX, MSG, EMLX, TXT, CSV, RTF, Thunderbird, Zimbra, Gmail, Yahoo, Microsoft 365, and Exchange Server.

Hiver - Manage Customer Support, Sales and Projects right from your Gmail inbox. Collaborate with Shared Labels, Shared Contacts, email notes, email reminders and email templates