It would be useful if the Tuner could tell you which chords had not been used. For example, I was looking for an easier chord for "th" than the one I had been using. Not so easy to see what 2-key chords are unused! It would also be helpful if you could filter it down to display only your 1-, 2-, 3-, or 4-key chords. Yet one more useful thing would be if "new" chords showed up regardless of filtering, since you may well want to add chords while you've got a filter on.