FriendLife - FriendLife is a great and interesting way of making new and dashing friends for free.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Twoo - With the millions of active and interesting people around the world, Twoo is one of the most interesting and practical means for finding the new people across the globe.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Qeep - If you are looking for a dedicated application freely allowing you to meet new people and find interesting friends, then Qeep is an application to whom you must give at least one try.
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.