My favorite unsung readline default is ctrl-o, for "operate-and-get-next”. If you’ve gone back and found a command from your history, ctrl-o will run it and then tee up the next command. And, if you hit the end of your history, it will cycle back to the point you initially searched to. So if you have a set of a few commands (e.g., foreground your editor, run make, test the results) that you tend to keep repeating, it will replace “up up up enter” with just “ctrl-o”.