I just came across this product on Etsy. She calls them cuddle sacs!
The crafter(MariahMade.etsy.com) is absolutely brilliant! This is what I’ll do with the ton of onesies that I will receive over the next 8 weeks :-) It could even be a way to use some receiving blankets that are too small to my liking :-)
(I don’t like onesies, but I love baby sleeping gowns)