What options exist for ad free web browsing on iOS?

In OS X I can use extensions in most browsers to block ads. This offers an distraction free browsing experience. For example: In Safari, Chrome and Firefox I can use **[Adblock](http://safariadblock.com/)** or **[Adblock Plus](https://adblockplus.org/en)** . Both extensions use filter lists which you can find [here](https://adblockplus.org/en/subscriptions) . You can also manually add filters and add sites on which you accept to see ads (e.g. apple.stackexchange.com). What options exists for ad free web browsing in iOS?