These are available to download on the App Store.
To practice visual design I created a sticker pack for iMessages. My goal was to create something that was fun, and would contrast against any images they were placed on. It was a fun change from the enterprise software I do in my day job.
I had a few old icons that hadn't been used, so they became the starting point for a sticker pack. I made their shapes and line weights more consistent and then started to research the most used emojis. From there it was mostly trial and error in sketch.