I stumbled upon a 2008 blog post by Adrian Bowyer, the inventor of the RepRap Project in 2005, where he talked about designing a coat hook so he could hang is lab cost somewhere other than his tripod. You can read the post here: http://blog.reprap.org/2008/05/economics-n-pl-management-of-household.html
Reading the comments, you'll see that the trolls were just as nasty then as they are today! It's amazing to see how the 3D printing world has evolved since those early days.
He used the Art of Illusion 3D modelling software to create this. I found his original source file and was able to load it and convert it to an OBJ file for importing into Fusion 360 so I could recreate and remix the coat hook. I mainly added some chamfers and fillets to soften some of the edges. My Fusion 360 file is included here so you can tweak it for yourself.
I have several of these in service and they print fast (30-40 minutes), are strong, and easy to use.
The author remixed this model.