If you're interested in a totally extravagant addition to your workstation, I have played with the Elgato foot pedal. It excels in recording videos (switching cameras/scenes, muting audio, etc.) where you don't want to keep touching a keyboard, but before upgrading my keyboard, I did enjoy having the left pedal set to copy, the center set to select all, and the right set to paste.
I also am using a customizable trackball and briefly experimented with devoting a couple of its buttons to copy/paste, but the foot pedal is much better for it.
I don't know of any keyboard shortcut document more complete than the one that Articulate already puts out. It's pretty comprehensive, but as you point out, it doesn't include shortcut keys for the timeline.