foldroid is a mail folder selection tool. For people who use mutt or a similar text mode mail reader, foldroid is a convenient tool to navigate through your mail folders. It shows how many messages are in each folder and how many of them are new. This, combined with a tool like procmail to sort mail messages of mailing lists into separate folders, makes selecting the right folder to read easy. Foldroid works best when you run it in a screen session, because it then starts every instance of mutt in its own screen.
Jaro Mail is an integrated suite of interoperable tools for GNU/Linux and Apple/OS X to manage email communication in a private way, without relying on online services (in fact, encouraging users to store email locally). It mainly features a system for mailinglist filtering, address-book integrated whitelisting, strong encryption and anonymous remailing, long-term email storage and archiving with functions for fast search and usage statistics. To accomplish all that, it makes use of solid Unix tools like Mutt, Fetchmail, Mairix, Msmtp, GnuPG, Abook, ELinks, and Mixmaster.