Not all of them have ocs/characters but some notable ones are "Corey" (magenta rabbit dude), Violet(purple fox though shes also attached to Rorie Taylor too), Ciel (though it's just a dog form of a Canon character), etc.
A lot of personal art is system related or its related to their interests, some of us like Fentanyl a LOT vs locket etc. So what we make and what we want to make changes and sometimes fursonas aren't even owned by specific alters just kinda shared.