If you like board games at all, there are a ton of board game adaptations. The unique thing about board game apps is they seem to be one of the few categories of games that can still get away with charging money up front for their audience, and not having any free to play garbage in them. They're about the only apps I still get for mobile platforms, nowadays.

Twilight Struggle, for example, is a very thematic and deep board game about the Cold War, that for years was the highest rated game on BoardGameGeek, and they made a great version for mobile. By the way, the board game was designed by Ananda Gupta also designed the video game XCOM: Enemy Within. https://www.pockettactics.com/reviews/review-twilight-strugg...

Through the Ages is another popular and deep strategy board game that's about building up civilizations over time, and it has a really excellent mobile version (so good that a lot of people prefer it to playing the board game version): https://www.throughtheages.com/

Race for the Galaxy is another good one, where you're trying to build up an engine, but faster than your opponents. Has tons of cards with unique properties and yet it plays pretty quickly. https://www.pockettactics.com/reviews/review-race-for-the-ga...

Pandemic is another modern classic game about trying to keep four different viruses contained as well as possible around the planet while searching for a cure. It's a bit lighter than the others I mentioned mechanically, but it can still be a tricky puzzle of efficiency, trade-offs, and pushing your luck, especially at higher difficulty levels: https://www.pockettactics.com/reviews/review-pandemic-board-...

There's a section on BoardGameGeek for iOS Board Game news (seems to also have Android and Steam in there also) that is my usual go-to to find out what board games are being adapted to mobile. Here's the link: https://boardgamegeek.com/blogcategory/108