This is how player colours map out. Each swatch is divided into topcolor and bottomcolor (intuitive). As you can see, 19 is the same as 9, so that's a no go.
Turns out that there are virtually no unique colours. These are the matching ones:
[*]0, 1, 7, 14
[*]2, 13
[*]3, 15
[*]4, 16, 24
[*]5, 17, 25
[*]6, 18, 26
[*]8, 20
[*]9, 19
[*]10, 22
[*]11, 21
And these are unique (though some may be a little tough to tell):
[*]12, 23, 27, 28, 29, 30, 31
Turns out that there are virtually no unique colours. These are the matching ones:
[*]0, 1, 7, 14
[*]2, 13
[*]3, 15
[*]4, 16, 24
[*]5, 17, 25
[*]6, 18, 26
[*]8, 20
[*]9, 19
[*]10, 22
[*]11, 21
And these are unique (though some may be a little tough to tell):
[*]12, 23, 27, 28, 29, 30, 31