I don't consider this a pattern so much as it is simply "instructions" on how to create a basic shrug. You could make this in any size using may different kinds of stitches. I chose to make mine with a v stitch.
To make this shrug you simply crochet a rectangular swath. Below you can see a close up of the stitch I chose but that really isn't important. The size of the piece should be determined by who is going to wear it. I just made it to fit my daughter.
You'll find several variations on this basic idea if you search shrug patterns. I glanced at a few of these but then just decided to make it up as I went. It's a very easy, straight forward but still wearable project.