What if you use black as your 2nd color? you could use all the pinks you want and it would never look sugary sweet.
Hst's set in one of the thousands of settings, diamonds, chevrons, spirals, furrows and rows. The list is endless.
I have seen a 2 color disappearing 4 patch that was wonderful.
A google image search or pintrest image search will give you tons of ideas, what about going trough your patterns and looking at them a little differently, try coloring them on graph paper and see what you think.