Like the title said. 
I often hit a key by accident and have no idea what has just happened. It would help me undo if I know what it does. A list like:
Shortcut     Function
a                xxxxx
b                xxxxx
Alt+1          xxxxx
Alt+2          xxxxx
..and so on

Hi. I do not know of a list that is sorted that way, but there is this, if that helps.
https://www.cakewalk.com/Documentation?product=SONAR%20X3&language=3&help=Menus1.181.html
All the best.

you can always go to "Preference / Keyboard shortcuts and look them up there.

Not a list but a graphical display of the shortcuts mapped on a keyboard display is available on the Sonar Resources and Utilities page. The program is called KeyBindingDisplay. The direct link to the program is https://sites.google.com/site/keybindingdisplay/. The list used to build the display was made around Feb/March 2015. The program uses a text file to build the display and may be modified to reflect updates and custom key bindings.

great, both ways work