I’m obsessed with using keyboard shortcuts to squeeze extra speed out of tasks, and one of my absolute favorites is the option of navigating Windows Explorer simply by beginning to type the names of the files and folders you want to select.
Since Renoise is already very heavy on keyboard navigation and speed, I think this feature would make a great addition in any instance where you have a list, be it the disk browser, the effects list, the instrument box, or the keys list in the preferences window.