This would be very useful. I had to store some of my Sandbox crafts in a backup folder because it was too hard to navigate. There is already a search bar for parts, so the technology is there. The 'first letter only' search would cut down scrolling time for sure. However, players who use naming conventions might have disproportionate craft under certain letters which would reduce the effectiveness of single letter jumps. Other organizational tools like folders could also help solve this problem.