I have a cage for Phoebe, who lives on her own at the moment, which she goes in when my chinchilla is out. I started just putting newspaper down in it as she has a litter tray in the corner, and it turns out she loves to shred!! Newspaper is a favourite as she can rip it all up and throw bits in the air, but she also likes thinner cardboard, like cereal boxes etc, as she can really destroy them..
My boy Nermal actually prefers plastic carrier bags... He doesn't eat them or even bite them, he just likes to scrunch them up, sit on them then dig away for ages! Think he likes the noise..
Those along with wood chews are all I need in my house now.. Although the tunnels sound good - got a feeling my two would love those.... Off to the shops I go!