Tony is a likeable guy, which is just one reason he isn't on Hannah's list. In fact, when she sends him a copy of the tapes, he immediately calls her parents to warn them. After Hannah has taken her own life, Tony spends his afterschool time following the twelve people on the list, making sure they carry out her wishes.
If you think about it, Tony is also playing an important role that Hannah – in her unstable and therefore selfish state – might not even have seen the need for. Tony is there for Clay throughout this process: he seems to be concerned for Clay and makes sure he is okay before he lets him out of the car. It's possible that Tony is our unsung hero. Maybe he's been there to help the people on the tapes get through it in a positive, productive way. Maybe he's made sure the tapes don't drive the other people on the list to follow in Hannah's footsteps.