I have used 3DE (Premium) and Spectrum Filaments PLA until recently.
3DE filaments have a specific given PANTONE value, whereas Spectrum Filaments use RAL codes.
I’m a professional photographer, but color me stupid, because I’ve actually never thought of testing whether their filaments are the correct value that they write in their specifications.
For color balancing purposes in photography, I’ve always just used my DataColor Spydr Checker 24, as it’s much more precise than only using 18% grey. It’s available on Amazon for around GBP 35 (I think I converted somewhat right, I’m more used to DKK, USD and EUR).
I know this isn’t exactly what you were asking for, but it was the closest I could get. But due to the difference in color response between cameras (fx. Canon and Sony, which are as far away from eachother as any 2 brands can possibly get), I need the other hues for a more precise color calibration and profiling, so 18% grey simply doesn’t cut it. Btw., I use Sony and I’m a former Sony Imaging ambassador.
I assume you know that you can go ahead and ignore everything that has to do with hex colors, due to the nature of additive vs. subtractive colors.