Everyone thinks the Modern UI in Windows 8.1 means a nearly complete abandonment of the mouse and keyboard for apps however, you might be surprised to learn that there are more than 60 keyboard shortcuts that can be used in the Modern Mail App.

Here is a sampling from the list:

CTRL + RReply
CTRL + FForward
CTRL + NNew Message
ALT + SSend Message
ALT + IInsert Attachment

You can see the entire list at the Mail Apps support page.

Not bad for a UI that is no good on non-touch devices huh?