Are there enough colors in the rainbow?

Every time I make a muslin, I do all the stay stitching and seams in the same color. Right now I am working on a contour bodice. So far I have used pink, blue, black and currently purple thread. It still needs adjustments so I will need another color from the rainbow.

The bodice block has the potential to be used over and over many times, so I want it to be right. Maybe orange?