What is your experience with board games? I'm very deep in the hobby, so some I enjoy may be too much or too boring for you. Do you have specific mechanics you enjoy or dislike? Are themes important to you?
There are many individual apps for specific games, but there are also a couple of websites where you can play tons of board games online
They should both have nice guides on how to play the games before you get started. I haven't personally used Tabletopia, I just know it is fairly popular. I have used Board Game Arena tons and have even had the subscription at times to support them and allow me to host more games. You can still join premium games, and there are plenty of completely free games. If I remember correctly BGA even has a more passive mode where it notifies you when it is your turn
As for individual games, I'm going to go with Wingspan. It is a birdwatching game. You collect bird cards, gain food for them, add eggs to their nest, etc. It is a super chill, entertaining game that you can easily grab a couple turns during ads
/boardgames
I've been playing Pokemon Emerald Rogue thanks to another user's recommendation in a separate thread. It's Pokemon the Roguelike. It is absolutely perfect in my eyes. With it being turn based you can easily set it down and pick it up. It's ridiculously modernized and customizable as well. Lots of love went into that ROM hack and I can't recommend it enough
I'm not really sure if this is what you are looking for, or even if they do packs (it was easy enough to search and click magnet links), but I was a big fan of MeGusta. I haven't downloaded in a while, so I don't actually know if they are still active. I'm more worried about size than quality typically, so I apologize if it isn't up to your standards