Exercises for C2 level

https://italianoperstranieri.loescher.it/materiale-didattico?livello=C2#level200

http://italianoperstranieri.mondadorieducation.it/livello/c2/

For english speakers

https://onlineitalianclub.com/free-italian-exercises-and-resources/online-italian-course-proficient-c2/