DAWebmail is an application that I made for my university (DA-IICT) email service. It's hosted on Zimbra, and Zimbra doesnt have an app of its own. We also dont have access to IMAP/POP numbers. To make things hard, the API currently being used isnt very easy to use, and there's scarce documentation. Hence, this application!
To access and view the application, you will have to login using a college email.
The application can be scaled to be used by any organization that uses Zimbra as their email service.
I have implemented material design as far as possible. Works best on L+ devices. Have also followed appropriate programming conventions, implementing interfaces, local broadcast receivers wherever necessary, and followed a structured manner of naming, and location of classes within packages.
Documentation and contributing to the repo here : http://bhardwajrish.blogspot.in/2016/01/contributing-to-dawebmail.html