I did a bit of research..
4 Green colours
3 Pink colours
3 Red colours
5 Blue colours
2 Brown colours
3 Greyscale colours
2 Purple colours
2 Yellow colours
1 Orange colour
2 "Other" colours (Pharos, Radioactive)
All the ones that are bolded are possibilities for a new colour.
I'm a bit dissapointed it's not fracture colours.