What are your favorite smartphone apps?

I used to play a lot of different games, the good thing is that you can find a lot of them in the app, and almost all of them are free. But lately I got pretty bored with them, so I'm also looking for something more interesting and exciting. At the moment the app https://sonatameditation.com relaxes me. Read more about it here https://play.google.com/store/apps/details?id=com.sonataapp , very cool