If your friend is already setting up a memory book for the baby then probably something with a personal touch would be great. Do you know how to do any crafts? Perhaps you could find patterns for knitted baby blankets or crochet baby blankets. If you don't want to spend an arm and a leg on a pattern book there are online sites that have free patterns for knit and crochet. There are also sewing patterns if you are really into it and want to make custom baby blankets from start to finish.
I, personally, like to take out the embroidery machine and play with it. I buy a few fleece baby blankets and "personalize" them. Sometimes I monogram them and sometimes I embroider the baby's name and date of birth if the baby is already born, that is.
Baby blankets are meant to keep the baby warm and comfy for sure, but the gift is really for mom. That baby isn't going to know if it's green or orange or purple or polka dot or whatever.