There are a lot of popular casual gaming applications for the Android platform.
Casual games have no targeted genre. They are usually simple and easy-to-learn. Anyone can launch such game and dive into it with ease. Mobile developers are fond of making casual games because they are not so complex and resource demanding as traditional RPGs, strategies, shooters, and others. Besides, they allow authors to experiment with gameplay and mechanic.
Despite genre is not an issue in this case, there are a lot of casual puzzle and logic games. And some of them can be skill based. Also, you can discover a lot of social gaming apps with simple rules like farmer simulators. The most of these games were transferred to Android from the desktop.