Are there any proxy sites at school that are not blocked?

[Viper]

None should work. Any proxies posted here are almost certainly already on proxy lists that schools admin and the content blocking software subscribes to. So they are likely already blocked.

School's are legally bound by the federal Children's Internet Protection Act to block proxies and the like.

Schools have to take this seriously to get certain technology funding.

All the proxies you try should be blocked by your school. That is because most schools use content blocking software. It blocks proxies 98% of the time because of their content (that they are a proxy), not because of the web address.
Also there are admins like me securing the system, adding any the system may miss (listed on proxy lists and even here) by adding them to the DNS blacklist.

You are very very unlikely to find one that works and even then it will only work for a short time until they know you are using it.

Your risking your computer rights/detention/suspension by trying to bypass their security.