A battery holder designed to hold:

• x16 AA
• x10 AAA
• x2 18650 Li-Ion
• x1 21700 Li-Ion
• x2 9V block

... batteries. 

This is designed with rechargeable batteries in mind, which means that the holes are a bit bigger to fit the different oversized NiMh batteries out there (looking at you IKEA LADA). 

If you have a lot of them, you can print two with different colors so they can be classified like need charge / charged. I printed mine with a .8 nozzle hence the quality seen in the picture. But at least it was a quick print :~)