All of these are excellent recommendations but my comment will be a little different. Some of those little-bitties won't survive but it's still nice to have something special to wrap them in. I have used orphan blocks to fashion into tiny quilts for donation and with that intent. When I was first interested in doing that, there was an online reference that it is best to not use some blues or yellows in those quilts as the infant already has a poor color. Of course, hospital white is not preferred--something cozy and comforting at a most difficult time.
Use of cotton is preferred because of static electricity possibilities.
I remember when my little grandson was born and my son first went into the NICU, he was shocked that "mom has already been here" when he found a quilt over the top of the incubator! Of course, it wasn't one of mine but it was a great comfort to my son during that time of uncertainty and concern.