Thunderbird is described as 'free, open source, cross-platform e-mail, news and instant messaging client. The project strategy is modeled after Mozilla Firefox' and is one of the leading apps in the News & Books category. There are more than 50 alternatives to Thunderbird for a variety of platforms, including Windows, Mac, Linux, Android and iPhone. The best alternative is K-9 Mail, which is both free and Open Source. Other great apps like Thunderbird are eM Client (Freemium), Evolution (Free, Open Source), Feedly (Freemium) and Claws Mail (Free, Open Source).
Historically, Icedove was a re-branding of Thunderbird by the Debian project, with minimal modifications, in order to resolve branding disputes. Debian since discontinued Iceweasel in February of 2017 after reaching an agreement with Mozilla over the use of it's trademark.
Take back control of your Inbox Set and forget Gmail plugin to automatically snooze emails till a certain time of day or week 1. Snooze Newsletters till Saturday - Declutter your Inbox by scheduling newsletters for Saturday morning
Email Insights is a Microsoft Garage project, a lightweight email client to get to your emails faster. It provides guided search in the form of superfast autocomplete, spell correct and fuzzy name search which means that users do not have to type out everything.