17hats - The all-in-one business system for entrepreneurs.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Salesflare - Simply powerful CRM. Automates your data to build better relationships and make more sales.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
GovWin IQ - GovWin IQ is the essential source for information, teaming and software solutions to help organizations find, manage and win government business.
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.