Teem - Cloud-based meeting room booking system
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
AskCody - Meeting management system for Outlook & Office 365.
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Skedda - Offices, co-working spaces, universities, sports venues, studios & churches are just some of the places that manage the use of their desks, rooms, courts, studios, halls and all other 'spaces' with Skedda
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.