I have built many keyboards - maybe close to 50 of them, but I also have a long list of failed projects.
Alps AEK Mysterium - got the PCB and plate working only to realize AEK keycaps are screwy with row 1 and 2 on stilts.
Faux Extent - may pick this one back up, but made a huge mistake ordering it in stainless steel - too hard to make screw holes and tap (I don’t even have a vice to hold it steady). Not sure what I was thinking.
Painted Retro60 - tried to strip the anodization leading to terrible chemical streaking - the paint wasn’t really a project, just a patch up. Once painted I just dumped it on mechmarket.
Most recently I started converting the Prism keyboard case for the Keyhole Absinthe - it is half way done, but I am tired of it and don’t like how it turned out.
I am sure there are more, especially if I count “in-flight” projects that I will probably never finish, lol.