Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Framadate - Make your polls
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.
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.
Dudle - Dudle is an online scheduling application, which is free and open source.