https://apps.apple.com/us/app/ct-art-4-0-chess-tactics/id113...
https://apps.apple.com/us/app/chess-king-tactics-puzzles/id1...
PS. This app is also mentioned in this article/HN post:
https://www.gautamnarula.com/how-to-get-good-at-chess-fast/
https://news.ycombinator.com/item?id=6791742
https://apps.apple.com/us/app/ct-art-4-0-chess-tactics/id113...
https://apps.apple.com/us/app/chess-king-tactics-puzzles/id1...
PS. This app is also mentioned in this article/HN post:
https://www.gautamnarula.com/how-to-get-good-at-chess-fast/
https://news.ycombinator.com/item?id=6791742