I purchased a flashlight (www.amazon.com/gp/product/B097DPZ2CL/) and a hip pack (www.amazon.com/gp/product/B00NXCK0XO/) and designed a clip to allow the flashlight to be carried on the outside of the pack. It's all parametric so you can adjust it for other uses.

This is version 1 of the clip. It would have worked perfectly if I wanted to glue it in place or if it wasn't situated so that I sit on it - it works itself off of the strapping on the side of the pack. I'm still posting it because it would have worked just fine on the other side of the pack or if I wore the pack differently.

Version 2 of the clip is available at https://www.printables.com/model/397463-parametric-flashlight-holder-for-shoulderhip-pack-