[Havoc7]

I’ve put so many hours into Dawncaster. It’s like Slay the Spire, but optimized for mobile (ie portrait mode). It even has a decent story. It also has a boss battle mode which it pretty sweet. It’s not free, but it’s worth it and gets regular updates with free card expansions.

I second Slay the Spire.
Undecember
Madness/Endless
Baldies Gate
After Place
Spark light