EssentialPIM Free makes extensive use of shortcuts. Here is the list of them:

Global:

Ctrl+Alt+S Minimize to system tray

Shift+Ctrl+T New Appointment

Shift+Ctrl+O New To Do

Shift+Ctrl+N New Note

Shift+Ctrl+C New Contact

Shift+Ctrl+M New Message

Shift+Ctrl+P New Password Entry

Switching Between modules:

Ctrl+0 EPIM Today

Ctrl+1 Calendar

Ctrl+2 To Do

Ctrl+3 Notes

Ctrl+4 Contacts

Ctrl+5 Passwords

Ctrl+6 Mail

Ctrl+9 Trash

General:

Ctrl+Q Focus on search box

In Calendar:

Ctrl+D Day View

Ctrl+W Week View

Ctrl+M Month View

Ctrl+Y Year View

Ctrl+E Table View

Ctrl+T Today

Ctrl+G Go to

Ctrl+H Hide/show completed

In To Do:

Ctrl+H Hide/show completed

In Notes:

Ctrl+R Add to root

Ins Add as Child

Ctrl+I Add as Sibling

Ctrl+Alt+Right  Move in

Ctrl+Alt+Left Move out

Ctrl+Alt+Up Move up

Ctrl+Alt+Down Move down

Ctrl+Alt+C Collapse All

Ctrl+Alt+X Expand All

while creating a new Note

Ctrl+D insert current Day

Ctrl+T insert current Time

In Contacts:

Ctrl+H Hide/show groups

In Mail:

Ctrl+R Reply to Sender

Ctrl+Shift+R Reply to All

Ctrl+W Forward

Ctrl+M Send

Ctrl+Alt+A Send and Receive All

Ctrl+Alt+R Receive All

Ctrl+Alt+X Send All

In Passwords:

Ctrl+Alt+U Copy User Name

Ctrl+Alt+P Copy PasswordIn Passwords

In text editing standard shortcuts are enabled: Ctrl+X, Ctrl+C, Ctrl+V, Ctrl+Y, Ctrl+A.

All shortcuts could be edited in Tools -> Options -> Shortcuts dialog.