Here are a couple of my favorite baby sweaters. I did not design them so I will show where the patterns can be found.
This first one I have made several times because it is so adorable. This one was made with Red Heart Soft Baby in "Kitten" and "Powder Yellow".
It can be found in this publication leaflet by Coats and Clark:
My other favorite was designed by Kelly at Bella Bambina. I have also made this several times. This one was made with Caron Simply Soft Shadows in "Soft Merino". I love the self-striping effect. This sweater buttons in the back which makes it easier to put over baby's head.
This pattern can be found at Bella Bambina.