A stackable economic paint bottle organizer it is designed for bottles from Ammo by Mig but could fit other similar sizes (3x8 cm).

The print is default .2 quality profile with .4 nozzle with default supports only on built plate for the overhang.

The box has a lot of holes to be cheaper to make but also resilient to be used as stackable storage and day to day handling/use.

On the top part you could make a stripe with primer and paint a small circle with each paint for easier spotting.

Have fun painting :)