As far as I know, all the novels that are coming out have been released apart from the one with the game and the audiobook versions from Fantastic Books. The sequels haven't been formally approved so you should be able to get hold of a few of them at least in various formats.
Are you looking for something in particular (which one do you not have )?
Are you looking for something in particular (which one do you not have )?
You may find a few of them cheaper if you get it directly from the publisher as well as other similar works, see
https://www.fantasticbookspublishing.com/store/
