I refrain from associating belts and/or color ranks with particular patterns because there are as many different systems as there are schools and instructors. Some schools have 10 kups (color ranks) while others only have 9, and once we begin talking about particular colors,... well, there are countless permutations of what was once, in ancient days, a purley black and white rank structure.
The only constant would be to learn and master the forms in the order they are listed on this site. If you are studying the WTF patterns, you would learn the Taegeuk and/or Palgue in chronological order before beginning your excursions into Koryo and those that follow. Most WTF schools require you to learn the eight Taegeuk (or Palgue) and the black belt pattern Koryo before testing for 1st dan. Then, each of the remaining WTF patterns coincides with the next degree of black belt, so that eventually one finishes by studying Ilyo for his 9th degree promotion test.
If you are at an ITF school, they require you to master patterns Chon-Ji through Chung-Mu for advancement to 1st dan. You would then study the next three patterns for each of the next degrees of black belt. (i.e. You would study the final three patterns, So-san, Se-jong, and Tong-il for advancement to 6th degree black.) After 6th dan, there are no new patterns to be learned.
This is only what seems to be typical of said schools, and is not a definite. For instance, at my first school there were 10 kup ranks, and one had to learn patterns Chon-Ji through Po-Eun in order to test for black. (You learned patterns Tan-Gun and To-San together at the same grade.) I have never since seen any school that practices this particular system. I am very fond of this method and think it quite natural, but realize it is not the traditional ITF system.
My point, of course, is that all schools practice TKD a bit differently from one another. If I were to associate color ranks with particular patterns, this would only serve to confuse the gross majority of users because my system would, 9 times out of 10, NOT coincide with their system.
Rank/Grade Color of belt (school 1) Color of belt (school 2)
__________ _________________________ _________________________
10th kup White White
9th kup Orange White w/ yellow stripe
8th kup Green Yellow
7th kup Green w/ one stripe Orange
6th kup Blue Light Blue
5th kup Blue w/ one stripe Green
4th kup Brown Brown
3rd kup Brown w/ two black stripe Brown w/ one red stripe
2nd kup Brown w/ three black stripes Red
1st kup Brown w/ four black stripes Navy Blue