There is nothing else to do but to get yourself a color fan from the plaster manufacturer. You can calmly consider which one suits your house. If you like a color, you can look at the different brightness levels of it and that way you get closer.
In the end, we liked 3 earth tones very close to each other, then the general contractor got us 3 sample patches of the plaster on a sample board and we held them up to the house wall and finally made a definite decision...
First of all, you need to know which plaster from which manufacturer.