Live Inbox - Live Inbox is a Microsoft Outlook plugin that helps you organize your email and search your inbox.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Lookeen - Lookeen is an enterprise search and desktop search software designed for individuals and enterprises. Its key function is Outlook search.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
X1 Search - X1's Lightning-Fast Search Software. Premium Alternative to Windows Desktop and Outlook Search.
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.