My business partner has a 3D Printer.
My 85 911 had storage for cassette tapes behind the shifter. I removed the cassette holders soon after I got the car, and I had a large square place to put my water bottle, but it flopped around.
I had him design and print my water bottle holder.
This is the bottom side after I filled it with expanding foam. I then painted it the interior color, and it works great. It securely holds a standard water bottle and keeps it cool for a longer time than just the bottle flopping around in the square hole.
If I ever get motivated, I will ask him to print it again, only from the bottom up, to make the top part smooth. It has a slight flaw in the upper right, but what the heck, it does not affect the performance.