I have done something with one of the onesies I bought a few weeks ago. I was nervous about ruining them, but today, just dove in.
I used double-sided heat bond light to put the fabric cutout onto the onesie. I had to iron at a higher temperature than recommended to get it to fuse, but it did eventually.
This onesie will still need to be stitched so that it can make it through the wash. I think if you get the heavier heat bond it will fuse and not require sewing but I was worried it would be too stiff for such a light piece of clothing.
I love this fabric. It has so many great images. I should definitely do more onesies from it. Here is a small sample I don't think I have shared before:
There is a great tree with an owl, the polar bear, moose and buffalo you can see here. I used the porcupine above and there is also a cute beaver and a goose.
I think all of these images would be great on onesies, bibs, blankets, etc.
Since I love the tree so much, here is a close up (you can see the beaver and goose in this shot too):
I am going to have to pick up some more stuff to appliqué this weekend!
The onesie post sewing:
I found a setting on my sewing machine that does appliqué edge stitching. I realised as I was sewing this that perhaps this images was a little complicated for my first attempt. Oh well, I think it turned out pretty well overall. Click the photo to see more detail!