I think that what makes a scrappy quilt really stand out is contrast. I love to see several fabrics in a similar family and then there's one "feature fabric" that is a totally opposite color. For example...lots of blues and greens and then a small spot of the feature fabric of brick, or tomato red. The reds are on the opposite side of the color wheel and they really make the blues and greens shine. Lights and darks work that way too. If you have lots of light fabrics, then throw in a charcoal, or dark, steel grey and see what happens...some tomato red might look good too...I really like tomato red.
~ Cindy