Dyche Mullin’s lab at UCSF has several handy stl files for 3D printed parts. For instance, these very handy boxes for storing and transporting 22 mm coverslips after they have been cleaned or treated.
They also have this delightful DIY coverslip spinner/dryer.
But beware, /u/machinofacture from Reddit has an interesting objection,
“I’ve made them before (out of abs) and they don’t stand up to being soaked in isopropanol. Although, I guess there are other materials that are perhaps more robust (petg didn’t exist at the time I worked with coverslips). You can extrude polypropylene but the problem is that it warps a lot and doesn’t stick to anything except itself. I did try to print a coverslip rack with that once but it didn’t work very well.”
Thanks to Dr. Peter Foster for originallypointing out this resource.