Baby Shower Advice

I've got a question for everyone that didn't find out the sex of their baby but still had a baby shower before the baby was born. 
We didn't think we would have a baby shower, so we ended up purchasing all of the major things (like furniture, car seat etc) and some basic clothes that would work for either sex. We really don't need any clothes for the first six months (a few cute outfits would be nice but we don't know the sex so I can't exactly suggest that to people). 
My sister said the other day she wanted to throw us a shower, which is so generous oF her! The problem is that I don't know what to ask for. I feel like we have almost everything we need except for a few minor or boring things. We are cloth diapering and have about half of the stash we need. We still need boring things like waterproof mattress covers and a nursing pillow but those aren't really gifts people tend to be excited about.  
Any advice on what to tell people when they ask what to buy? I'd like to put together a list for my sister for when people ask but I just don't know what to suggest.