How to get overview of keyboard shortcuts from OS X?

I would like to know about keyboard shortcuts, that is, shortcuts that are mentioned nowhere in the menus, nor anywhere, and must be found by stumbling upon them in sites like these, but still work.

Examples:

• ⌘⇧., which shows or hides hidden files in a save or open dialog box.
• ⌘⌥⏏, which causes the computer to go to sleep.
• ⌘⌥⇧⌃., which runs sysdiagnose and shows the results in the finder.

Does anyone know of more of these or how I can get an overview of these shortcuts?

(Many of these are not that well hidden, but I basically copied this list from my website.)

• Holding ⌥⇧⌘⎋ for a few seconds force quits the frontmost application
• ⌥⇧⌘Q logs out without showing a confirmation dialog
• ⌃⌥⌘⏏ restarts without showing a confirmation dialog
• ⌃⌥⇧⌘⏏ shuts down without showing a confirmation dialog
• ⌃⇧⏏ puts displays to sleep
• ⌘F1 toggles mirroring displays
• ⌃F2 focuses the menu bar
• ⌃F4 cycles through windows on the current space
• F5 shows the completion menu
• ⌘F5 toggles VoiceOver
• ⌥⌘F5 shows accessibility options
• ⌥⇧F11 and ⌥⇧F12 change the volume in smaller increments
• ⌃⌘D shows a dictionary popover
• ⇧⌘L searches for the selected text using the default search engine
• ⌃⌥⇧⌘. starts recording a sysdiagnose report that is saved to /var/tmp/
• ⌘⌫ selects buttons like Don't Save in dialogs
• ⌅ selects the default button in dialogs even when the focus is on a multi-line text view
• ⌘I shows a list of files included in an installer in some installer windows
• ⌥⇧⌘S is Save As in many applications that use auto-save
• ⌥⇞ and ⌥⇟ scroll a page up and down and move the caret
• ⌥↩ and ⌥⇥ insert a newline and a tab even when a form field has focus
• ⌥⇧↓ and ⌃⇧E select to the end of a paragraph
• ^L centers a view around the caret
• ⌃O inserts a newline after the caret
• ⌃T transposes characters on the left and right side of the caret
• ⌃' and ⌃" insert straight quotes even when smart quotes are enabled
• ⌃⌫ converts for example ä to a
• ⌥- and ⇧⌥- insert an en-dash and an em-dash in many keyboard layouts
• ⌥], ⌥⇧], ⌥[, and ⌥⇧[ insert smart quotes in many keyboard layouts
• ⇧⌘↑ focuses the desktop in Finder
• ⌃⌘↑ opens the folder shown on the title bar in a new window in Finder
• ⌃⌘F opens a Spotlight window that is set to search by name by default in Finder
• ⌃⌥⌘5 sorts items by date modified without grouping files under sections in Finder
• ⌥⌘I opens an inspector window that shows the combined size of the selected files in Finder
• ⌅ enters rename mode in iTunes
• ⌥⇧⌘T takes a photo without a timer or a screen flash in Photo Booth
• ⌥← and ⌥→ scroll a page left and right on pages with horizontal scroll bars in Safari
• ⇧⌘↩ opens the address on the location bar in a new tab and focuses the tab in Safari
• ⌥↩ downloads the address on the location bar in Safari
• ⌥⇥ cycles through links in Safari
• ⌃⌥⇥ inserts a tab when a form element is focused in Safari

You can use Shortcuts or KeyCue to show a list of all keyboard shortcuts displayed in the menu bar. I also posted an AppleScript like them at https://superuser.com/a/415221.

Many of the default text editing shortcuts are defined in a property list inside AppKit.framework:

plutil -convert xml1 /System/Library/Frameworks/AppKit.framework/Resources/StandardKeyBinding.dict -o - | pl | grep -v noop: | ruby -pe '$_.gsub!(/[^ -~\n]/,"\\U%04X"%$0.unpack("U*")[0])'

Other lists of keyboard shortcuts:

• http://apple.stackexchange.com/questions/183
• http://rixstep.com/2/20040510,00.shtml

I find the free app CheatSheet is a great way to show what shortcuts are available, Install it and it runs in the background, then just hold the ⌘ key down for a couple of seconds without choosing an operand to get a list of all active short cuts of the current application.

CheatSheet uses the Accessibility API to read the menus of the current application, but you need to turn on support for Assistive Devices to allow this - the app shows instructions how to do it. Because of this, it can only show the shortcuts that are obvious, and it might not show shortcuts that are not displayed via your apps menu bars, but nevertheless it's a brilliant way to learn an apps common shortcuts - once y ou have held down the key to show the list, you can then continue to type in the shortcut you want, so it doesn't need any new workflow to use it effectively, just a pause if you are not sure what you want to use.

If you look in the keyboard section of system settings there is a section on keyboard shortcuts where they are all set. You can also create your own custom configurations. Or if you really want to get crazy, combine this with your own AppleScript services to make a shortcut for anything.

Edit: I really don't think there are any secret shortcuts; they are all configurable and documented here.