Newton Mail is an email app for iOS and Android devices, as well as a web application for desktop. It is designed to help users manage their emails more efficiently, streamlining the process and helping them avoid information overload. It has several features that make it stand out from the competition, including a unified inbox that allows users to view emails from multiple accounts in one place, as well as an AI-powered assistant that learns from user’s preferences and can suggest relevant tasks such as follow-up emails. It also includes powerful search capabilities, customizable swipe gestures, snoozing and scheduling options, and integration with other popular apps, such as Evernote, Google Calendar, and Dropbox.
K-9 does not support real-time push and sync between multiple devices.
It has interesting features and makes the mail inbox less cluttered.
The discontinued Opera Mail is no longer updated and no longer supported, but the latest version, 1.0.1044, released in February 2016, can still be downloaded from the official website.
More features, much more customizable, looks great and works perfectly.
Thunderbird
K-9 Mail
Microsoft Office Outlook
eM Client
Evolution
Spark
Apple Mail
Mailbird
Postbox
Mailspring
Claws Mail
Geary
Opera Mail
Airmail
Sylpheed
Polymail
TypeApp
Microsoft Mail and Calendar
Spike
The Bat
UI ugly, but in terms of features and functionality, the best alternative I could find.