Carol d- I love your idea! I was going to suggest the same thing. The Goodwill we donate asks that items be in "gently used" condition so I would not bring them undergarments. I have been saving my husband's old undershirts, socks and other stuff we won't donate to stuff a bed for my dog too. There are some great beds for sale on Etsy that are ready to be stuffed.
BTW- for bras that are still in ok condition, consider donating to The Bosom Buddy Program (www.brarecycling.org). I may have originally heard of them here, I can't remember. They ask for washed bras (sent at your own expense) and then refurbish them and donate a portion to needy women. I sent a bunch a couple months ago and got a nice thank you card from them. I LOVE that they are are getting another life!
I don't have a baby, but what a great baby quilt fancy socks would be, not the foot part but the ankle, and I wear knee highs so thats twice the fabric :)..Got this idea from the dog blanket, I am going to cut up every bad sock and tee and recycle it into my friends dog blanket and I do have some AWESOME socks that when they wear through, a baby of mine( here's hoping in the future) would LOVE :)