Buy more fabric in coordinating colours and make a patchwork lap quilt ... or larger!
It's hard to know what all to suggest, when we don't know how large your leftover pieces are!
Keeping with the theme, you could make her a pair of eye covers (to block light when sleeping)!!
Other ideas ... more make up bags, coin purse, slippers .....
Actually the best idea ... make something for your son, so he can enjoy it too!