This app was mentioned in 2 comments, with an average of 3.50 upvotes
This might be below your level, not sure.
But, I really like practicing declensions with Yazh. I think it's Android-only as well.
https://play.google.com/store/apps/details?id=com.yazh&hl=en
Regarding the vocabulary, I created this Memrise course. Roughly 1000 words sorted by themes. I suggest setting Memrise review sessions to 50 words per sessions and learn level by level. I regularly update it when I have some time. Lately I've been mostly focusing on sentences/examples for the words I had previously added.
As for the cases, I personally think these tables are the most comprehensive ones. There are also exercises on the same website to work on them.
App-wise, Yazh is great to work on cases as well.