Waldo Bronchart interesting little utility shows you interactive charts of the keyboard shortcuts in Lightroom & Photoshop. You can hold down various modifier keys to see what they do in combination with other modifiers + letters, etc., and you can search for shortcuts (e.g. everything related to Print).
Hmm—this would actually be kind of brilliant for the teams to use when finding open shortcuts (never an easy task!).
[Via]
I saw this a while back and thought it very nicely done, but not so useful for finding open shortcuts as you think, because they are at present incomplete.
All the second monitor shortcuts for LR are missing for example, shift + G, N, E, etc and I seem to recall spotting some other omissions/mistakes too. Blending modes in PS for example need the shift modifier and the ‘+’ key going in opposite direction to ‘_ ‘ is missing.