Has helped me alot as a beginner
Chess King's apps take you through learning chess in a very methodical satisfying way.
Goof chess primer
Satisfying and it is free
Nice app, good tactics examples, nice animation.
Fine training tool.
* Added Greek
* Support subscriptions, you can buy subscription to all courses at learn.chessking.com
* Improved home screen design
* Improved refutations showing
* Various fixes and improvements