Gütermann retail thread sold in the US is labeled with a different set of color numbers than the wholesale versions sold on tubes, such as those available from Wawak. Gütermann Mara 100 All Purpose Thread – Tex 30 sold at Wawak is the same thread as the all-purpose thread sold in retail, but you get ten times as much as is on the small spools. So it’s a good deal to buy the larger spools of colors you use a lot.
If you ask, Wawak will email you a conversion chart so you can compare the 262 retail color numbers to the wholesale numbers. It only includes the numbers, not the retail color names, and is sorted by the retail numbers. It also looks like it has been photocopied a few times and is hard to read.
I have the wholesale 700 color thread chart, and I wanted to be able to easily convert the color numbers both ways, so I found a list of color names, added them to the list, and reformatted it. I included one page that is sorted by the retail numbers and one that is sorted by the wholesale numbers.
Here is a link to download the pdf of the new and improved Gütermann Thread Color Number Conversion Charts. [I updated the charts on 1/4/2021 to correct some color names based on this chart from Blackbirdfabrics which I checked against other online sources. Note that online retailers may use different names for some colors. The partial image below is from my original chart, not the corrected one, FYI.]
When I compared the retail thread spools that I have to the thread chart, it looks like not all of the colors are exact matches, and thread color varies a bit between dye lots, so keep that in mind, but it should get you close to the right color.
Let me know if you find any errors in the chart.