This protective sleeve is 3d-printed in an incredibly strong and durable, but also highly-flexible TPU filament from Push Plastic.
It fits the mintyPi (all versions, including the Lite!) perfectly, and even has spacers on either side so your power switch and/or L/R buttons won't catch on it. It should protect your mintyPi from getting scratched up and will let you toss it in your bag without worrying too much.