Warner and Rocksteady announced a long list of new downloadable content for those players who have purchased the Season Pass.

So, you have successfully played and finished Batman: Arkham Knight, and you have bought the Season Pass and you wonder what is still out there? Warner Bros. and Rocksteady have an answer to everything you want to know. They have  published the full list of DLC to arrive by the end of December through the Forum for the last game in Arkham trilogy (sorry Origins, you are not on that list).
The rest of the DLC for Batman: Arkham Knight revealed
The things we must mention are new add-ons for Batsuit and Batmobile from the next year’s Batman v Superman: Dawn of Justice, with a note that this DLC will be available to anybody but the owners of Season Pass will have earlier access. Players asked that Batman looks like in a movie from 2008, The Dark Knight, as well as the possibility to drive a Batmobile that we could only watch in Arkham Asylum, 2009. And they will, they just need to wait till December.
There are also AR Challenges, and lots of them, and the last two Arkham episodes focused on the story will be about Robin and Catwoman. What exactly to expect you can read here, and we hope that the next news will be how they got a PC version
From the remains of the AR Challenges which there are many, and the last two episodes of Arkham that target story will deal with Robin and Catwoman. What exactly can you expect all can be found here, and we hope that the next news will be how they finished the PC version, and that they are ready to put on sale again.