I use Launchbar to maintain my Clipboard history with 30 items in the buffer. I’ve been using this for at least a couple of years and it’s a staggeringly productive feature.
With a single keystroke, I can see the contents of the last 30 copy/paste actions, use the arrows to move between them and then paste that into my current activity. It shows some useful info about where the copy data came from (useful for when your mind goes wandering).
Today, I accidentally pressed the space bar and got a surprise when QuickLook was invoked.
I thought that this was neat enough to tell you about it.