I really like Krohm Koala's 3 bottle SodaStream stand to store my empty bottles, but there's no place to store the bottle caps.

So I made a base plate that attaches to the above model.  Now both the bottles and caps are stored neatly in the same place.

I printed both models in ABS, 0.15mm STRUCTURAL, 15% infill, no supports. I used super glue to hold the two parts together and clamped until the glue cured.