Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3875040.
Quick and dirty remix of this Alexa wall plate adapter. All credit goes to bkahan, I just measured my wall plate and made it the right size. Feel free to use this as a reference to fix the original thing and I can delete this one if you want. Tested on an Insignia USB outlet and a standard GFCI outlet and it fits. Added holes so you can run USB through the bottom if you have a USB outlet like mine.
Also obligatory warning to use this thing at your own risk. Take the necessary precautions when working on power outlets, and of course there is a risk when using 3D printed plastic compared to the UL listed, self-extinguishing faceplates that you can buy at the store.