I’m happy to release an initial version of the Ardour shortcut cheatsheet - a handy 2-sided tri-fold guide to almost every shortcut in Ardour. There is one version for X Window (Linux, FreeBSD, etc) and another for OS X (reflecting different conventions about modifier keys in both systems.) These cheatsheets will hopefully convey a lot of Ardour’s power that is generally hidden to most users. The current cheatsheet reflects the binding set that we call “mnemonic”, configured for a US keyboard with a keypad. There are other binding sets available, but no cheatsheets for them at this time.
Please note that these bindings do not correspond precisely to the "mnemonic" bindings released with Ardour 2.8.2, but the differences are rather small and involve rarely used commands. If you want to get this exact set of bindings, you can download the "new" X Window or OS X bindings file and install it as ~/.ardour2/ardour.bindings. These are not necessarily final versions - watch the website for any updates, and please feel free to leave comments, corrections etc. in a comment. Finally, please feel free to throw an extra US$1 donation toward ardour.org if you find this cheatsheet useful. Thanks.
In a future release of Ardour, there will probably be a tool that will generate cheatsheets based on your own customized bindings. You can modify all keybindings in Ardour via the key bindings editor dialog. On X Window, you can also do this directly on a menu - just point the mouse at the menu item and press the new keybinding.