If you're into simple games, there's one called Lato from F-droid. It's just a snowboarding game where you click to jump over boulders and cliffs with a changing atmosphere and relaxing music. It helps me ease my mind.
This is interesting, it looks like a remake of Alto's Adventure. The control sensitivity takes a moment to get used to, but the background is just as nice as the original, and the music is indeed relaxing