If you are interested in open source and privacy friendly android apps you should have a look at this two projects.
The group Privacy Friendly Apps are a collection of Android-Applications, which are optimized based on privacy. This means that only a minimum of permissions is used. There are no unnecessary permissions, e.g. a torch application would ask for a permission to read the contacts.
Simple Mobile Tools: A group of simple, stupid, open source Android apps with customizable widgets, without annoying ads and unnecessary permissions.
They develop camera, file-manager, gallery apps and more. You can find the apps on github/f-droid and play store.