Allow macros
It would be really nice if I could define key macros that are sent when I press a certain shortcut.
For example, to undo typing in Bash you can type ^X^U
but I would love it if I could just type Undo.
Other examples would be hotkeys to perform actions in tmux, favorite commands that are not available on new VMs etc.
So something like the Shortcuts preference pane, but with (encoded) strings instead of actions.