You can configure HTTP Switchboard in such a way as to make it behaves close to how RequestPolicy for Firefox works.

Here is how the matrix would look like:

In the above setup, all the request types are graylisted by default, and "Auto-whitelist page domain" is enabled.

I created a backup file which can be restored (from the About tab) in order to make HTTPSB behave close to how RequestPolicy works:

https://raw.githubusercontent.com/gorhill/httpswitchboard/master/assets/httpsb/setup/httpsb-requestpolicy-like-setup.txt.

Remember: Restoring data from a full backup file will overwrite all your settings!