Here are just a few of the blocks in the Auntie Alice quilt. Darks don't always have to be blacks, navys and grays - they can be dark reds too.
That lower left square is actually printed fabric. I did not piece that - although, I could have if I didn't have enough darks.
I have some fabric that has candies on it. Why on earth I bought it, I'll never know. It works here because the overall feel of the little piece is dark.
After trimming the backing of a quilt, one is quite often left with little strips of fabric - like this one. I will use anything that comes to hand when I'm piecing - especially if it really doesn't matter. All that really matters is the value of the overall piece. In this instance, it's light.
Even stripes can be used.
Anything goes. Just have fun.