If you’ve perused the usual 3d print file sites, you’ll notice that most 3d print designs are either excuses for using your printer*, or slap-dash models to get something done.
I was blown away by the excellent designs at Goodman Lab. This is proper design and engineering for the purpose of making useful products, that can be 3d printed. They also are taking a reasonable approach to running a viable business and community.
*Including some stunning mechanical and art designs.