My lovely and talented wife has very cool post on choosing wool for an appliqué project:
Before beginning a new project though, I usually spend some time thinking about the medium I will be working with, which is the various types of wools and threads. There are so many interesting options out there! How do you know what to choose? For a quick-start project, I will share a few of the basic supplies I like to consider for making a wool appliqué project, including the fabrics and felts, needles and threads.
If you’re so inclined, check it out!