So I just found this idea in an email to myself from five years ago. Still haven’t seen anything quite like it, even at a ad-hoc level. This idea pertains to an OS-wide level, ideally.
When in a shortcut-heavy program like Pro-Tools, iPhoto, iTunes, etc., it could be useful to have a little optional window pop up when hitting shortcut keys, like
option + command,
shift + command, etc., and in this window would be listed the most frequently-used shortcuts by that user, and a quick description of what those shortcuts do.
For instance, in iTunes, if I were to hit:
The little window would fade in, and list:
option + command + E - Equalizer option + command + L - Downloads ... ...
This could be dynamic, where if you hit just
command, every shortcut that uses the command key would show up in the little window (starting with the ones most frequently used, then if you hit
shift, it would filter to only shortcuts that use both of those keys.
The closest thing I can think of is in, say, a right-click context menu in Finder on OS X, if you hold down
option you’ll see the contextual menu items change.