This is an old post, and I just stumbled on it while searching for something else, but ^K is "<ctrl>k" in the Toolbar Shortcut maker. KP_Enter can be also entered as <ctrl>m ... it is one character shorter!

<ctrl>c is very useful, it breaks execution of a command-line app.

A very useful shortcut for me is:
It is useful because lots of command-line apps bug you by asking you to hit "Y" if you are sure you want to do something, and it is nice to just hit a toolbar button instead of pulling up the screen keyboard or whatever.

EDIT: A couple other useful ones: | (pipe) is "bar" and _ is "underscore". Both are a pain to type (at least for me) on the virtual keyboard.

EDIT2: Note that you don't need the " . " (space-period-space) between characters, just use a comma.