None of the commercially-available racks would work for me. I need to see the labels on the bottles. So the racks that store the bottles horizontally are no good. And the racks that store them vertically cover the labels or enough of the labels that I can't read them. I made myself a rack with shelves tilted about 45 degrees. First I used scraps of thick styrene from a yard sale sign. But it wasn't strong enough, so I made a better one out of scraps of luan plywood.
Along with the requirement that I can read the labels, I had another requirement that the rack fit in that drawer in the little Rubbermaid storage cabinet I use. The new rack works well for me. And when I switched from that storage cabinet to a large toolbox for better portability, I found that the rack fit perfectly. The only problem I may have is if I add more acrylic colors.
Paint jars I label on their tops with small gummed labels: