If your Outlook is meant for professional emails, then Grammarly is a must-have add-in.
Key Benefit: Write better emails without grammar and spelling errors. To stay on top, the add-in allows you to switch from the calendar to the other views like the inbox, contacts, tasks, and notes. You can customize the size and opacity to your liking. The Outlook on the Desktop add-in pins the calendar on the desktop, so you don't have to launch and click through Outlook's screens.
To get things done, you should schedule it. Key Benefit: Pin the Outlook Calendar to your desktop.