A variety of White on White, off white, cream.
Darks, brown, black, navy
All brights ( for the Kaffe Fasset crowd)
Large Prints for the Amy Butler/Michael Miller bunch-Great for clothing, purses, totes as well as quilts
Pastels
Novelty -Kid Prints
Batiks
I really didn't answer your color question. You are very safe with a variety of Greens, bright to muted, used alot in applique.
Purple, violet are the hardest to find.
Don't like burnt orange, though I attended the U of Texas-Austin
CONGRATULATIONS ON YOUR NEW STORE. Let us know if you are selling online.
D in TX