I couldn't find one I liked so I decided to design my own.  

I print these in PLA+, 0.28 layer height, 6 walls and 45% infill with a 0.6mm nozzle.  Supports everywhere and they break off pretty easy and clean with the right settings.  Maybe a bit overkill but I have printed lots of these and never had one fail.

Mount on a wall or under a shelf.

Should take about 2.5 hours to print and takes about 55g of filament.  

Battery holders here: www.printables.com/model/237605-milwaukee-m18-battery-holder