Please look at this picture I took from a Japanese game:

I am a person who notices little details a lot, and this pad with the tiny sparkles is unique and solitary only to this exact location in the game. It's a little difficult to find it (16% chance), and it has two colors which are not used elsewhere in this stage, and I am certain, not anywhere else in the entire game. So it's a truly rare color combination.
I will list the 6 shades here:
██████ & ██████
I am always interested to read tutorials about picking the correct colors for art. Very rarely I find some source which discusses rare colors.
Now, these two colors are very spiritual in my eyes, and they look very interesting. I don't remember seeing this combination in my life much, in fact, the closest comparisons would be Friday the 13th night landscapes and Super Mario Bros. 1-UP mushroom (both NES games). Other than that, I can't recall seeing these two colors combined. They give me the feeling of....mold and spores? something like that? It's definitely a combination that could be used for mushrooms with green dots, such as the 1-up mushroom. But it could very well be reversed, the green being dominant.
Do you know any rare color combinations? Two colors? Three colors? I would like to discuss color picking itself as well, if that's okay. Since I am not yet very good at choosing the correct colors, but I am getting better.
I have sensitive eyes and I love to discuss color theory and usage, so consider sharing your thoughts please!

