It's possible to browse Derpibooru using Tor Onion Services (aka Hidden Services).
The advantage of onion services is that by using the Tor anonymity network, you can bypass censors in your country or filters in your service provider's network.
Using an Onion Service as opposed to browsing Derpibooru through the Tor Browser Bundle allows you to have end to end security within the Onion network rather than relying on an exit node to not be censored.
Points to note
Because we can't identify users by IP address when using Onion Services, it exposes the site to abuse. To counter this, we require that you make an account and sign in before you can interact with the site. You can register from the Onion Service as you normally would, or log into an existing account.
You'll get a HTTPS error when connecting as we don't have a HTTPS certificate issued (yet!) for the Onion addresses. You'll have to manually approve the certificates if using Tor Browser Bundle.
The Onion Service will be slower than using the site directly. However, it will work - regardless of censors - so long as you're able to connect to the Tor network.
The main website can be found here: https://ronxgr5zb4dkwdpt.onion