I believe a light novel was in the works based on Azura, but as far as I’m aware it got scrapped. Other than that I don’t believe any other official media exists or is planned which is a shame.

As far as I know, there hasn’t been any official word one way or another, and any time Terrace and crew are asked about it, they say they’re open to the idea but don’t have any particular plans.

No word since the ending of S3, and Dana Terrace left Disney. I wouldn’t hold my breath for more media related to the IP.

Hopefully we get an official Lego set from Lego Ideas. It’s currently sitting in the review process.