Chess studio app and other "must have" apps.

I have lichess app, that have no limit tactics for free. I do my daily 25 tactics of gold subscription in chess.com first anyway, and if I want more I go to lichess :-)
Also ChessClock if you play on boards with time is pretty convenient. And.. if you wanna challenge yourself against the Master, you can try Play Magnus, where you play against a virtual Carlsen with different algorhytms for his ages.

Are you referring to the Chess Studio available through the Apple app store? What you're describing is just what I want.