two "new" aesthetic tags

I found out earlier today that there wasnt a tag for this, so i went ahead and made/fixed them.
 
duotone is for images that have only two colors (like >>2001189) and tritone is for images with only 3 colors (like >>2001305). Quadtone is also a thing that exists but i havent found any images that it applies to yet.
 
https://derpibooru.org/tags/duotone  
https://derpibooru.org/tags/tritone
 
I hope you guys get some use out of these :D
 
(ps, i had to ‘edit’ tritone bc it was incorrectly tagged on a few images)

@danmur15  
Your tritone example has four distinct tones, and most of the stuff relevant to this will be found under limited palette