Once you've made your yarn, there are lots of ways to use it. On You Tube, there are lots of video tutorials for T-Shirt Yarn projects. If you specifically want a crochet project, it's best to include that in the search, as there are a lot of tutorials for sewing and handwork projects.
Here's a nice rug.
Here's a pouf.
Here's another rug.
The three videos above are from the You Tube channel Tuteate.
Here are a couple of summer scarves, which use different cutting techniques.