The Android operating system is one of the most popular open source projects used by more than 2.5 billion devices. There are plenty open source apps for Android. In this article, you can find some of the most popular apps for Android.

NewPipe

NewPipe is a free and open source YouToube client for Android that doesn't require any account or Google Service. 

Lawnchair Launcher

Lawnchair is a simple and clean launcher for Android. It's a fast and snappy launcher that looks like the Google Pixel Launcher.

Amaze File Manager

Amaze File Manager is a light and smooth open source Android app based on  Material Design guidelines.

Shuttle

Shuttle is a local music player for Android that includes a built-in equalizer, sleep timer, folder browser, widgets, and more.

FairEmail

FairEmail is an privacy-oriented open source email client for Android. It works with all major email providers, including Gmail, Outlook, and Yahoo.

Moonlight

Moonlight is an open source implementation of NVIDIA's GameStream for Android.  This app allows you to stream your full collection of games from your Windows PC to your smartphone.

Markor

Makor is a free text editor app for Android. This app helps create notes and manage to-do lists using simple markup formats like Markdown and todo.txt.

Sources:

https://www.theverge.com/2019/5/7/18528297/google-io-2019-android-devices-play-store-total-number-statistic-keynote

https://unsplash.com/photos/TbLdLyigPj4