DockbarX - DockbarX is a standalone dock that groups and launches applications.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Gnome-Pie - Gnome-Pie is a circular application launcher for Linux.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Synapse - Synapse is a semantic launcher written in Vala that you can use to start applications as well as find and access relevant documents and files by making use of the Zeitgeist engine.
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.