I recommend an assortment. Get some clothes - 3 to 6 month size as she will probably get several new born. A couple of little clip on toys. Plus, a baby medical type kit, diaper cream, binkies, bottles, towels...... You can add a special item such as a nice frame that could show pictures of all her children. A book for her teenagers about the baby....
This can all be but in a nice basket. Plus, it has the benefit of being very use ful no matter how many items like it she gets - the problem with not being registered.