This is a remix of BrownDogGadgets's "game controller" style micro:bit Holder. Original has a very nice and intuitive design. 

I use the micro:bit in kits for groups. The original was too thick to fit in the individual kit-boxes. So, I removed the battery holder. I use Velcro dots to secure battery pack instead.

I can print this with no supports on a Creality V3 KE printer (0.2 mm layer height) and only have a few strings to remove. The micro:bit still snaps into place nicely. The holder really helps keep the micro:bit from wear and tear. Additionally, I can fit 6 copies on the build plate at a time (20% gyroid infill) and print in about 6 hour batches.

Thank you BrownDogGadgets!