pop3download is a script that downloads e-mail from a POP3 or IMAP mailbox. It was originally created to work around certain fetchmail bugs, and now works as a very limited and simple alternative to it. It can keep files on the server, force CRLF line endings, poll at an interval, and pass mail through an MDA for filtering.
Gaze is a lightweight Gmail checker that sits in the system tray and notifies you of new messages in your inbox. You can configure how often the program will use the ROME API to check the Atom RSS feed for your inbox, as well as optional combined notifications, custom browser actions, theming, and more.
Built upon Maarch Framework, Maarch LetterBox is a complete mail management solution. It is developed exclusively by its user base. It handles incoming, outgoing, and internal mail. It ships with an inline editor to generate mail or answers from templates. It sends alerts and notifications on new mail, late mail, etc. It manages mail circulation between users through virtual mail baskets. It logs every action on documents and on the configuration of the application. It offers tools to monitor mail activity.