There have been several things in the apple II and Mac arenas that have been 3D printed as well. The square power light cap for the II+ keyboard has gone through several iterations to the point where it is fast approaching a true replacement. The most notable item is the eject gear for the Apple 3.5" disk drive that has finally been (dare I say it) "perfected." After several trial and errors with material (I know next to nothing about 3D printing mind you) there are two different people who have made and sold the replacement gear to those of us without 3D printers. The initial runs broke after only a few uses but were quickly replaced with newer batches that so far have held up with repeated use. The gear is a known issue with these drives as they have aged, especially in drives that sat for long periods of time without use. The grease congealed and the drive mechanisms got sticky and the stress of attempting to eject a disk snaps the gear (the original is a plastic gear to begin with). So far the replacements have worked well. Tony