grexit.comSoftware by GrexIt Software
Mailor - Shared inbox, team portal and smart notifications
Front - multi-channel inbox service for collaborative teams
Airmail for iOS - One of the best Mac email clients, now on iPhone
Gmelius for Gmail - Gmail on steroids. Scheduling, reminders, follow-ups & more.
eM Client - eM Client is a fully-featured email client for Windows and macOS with a clean and easy-to-use interface. eM Client also offers features for calendars, tasks, contacts, notes, and chat.
Juphy - Manage all your social media conversations, comments, reviews, and support requests in a single, shared inbox. Boost Sales on Social Channels via Messaging.