
- AppMonk (utility) [sources] 
The AppMonk toolkit is a collection of utility classes for Android projects. 
- DroidKit (web framework) [sources] [site]
Collection of extended Android APIs 
- GreenDroid (UI) [sources] [site]
Makes UI developments easier and consistent through your applications. 
- Droid-Fu (utility) [sources] 
A utility library for your daily Android needs 
- android-screenshot-library (utility) [sources] [site]
Android Screenshot Library (ASL) enables to programmatically capture screenshots from Android devices without requirement of having root access privileges 
- android-alarm-database (utility) [sources] [site]
This utility class is a easy-to-use wrapper around system Alarm Clock application intened to be used instead of custom alarm databases on Android platform, in applications like Night Clock, etc. 
- ACRA (utility) [sources] [site]
Application Crash Report for Android 
- ZXing (barcode/QR-Code) [sources] [site]
Multi-format 1D/2D barcode image processing library with clients for Android, Java 
- jjil (image processing) [sources] [site]
Jon's Java Imaging Library, for mobile image processing 
- AndroidLibs (contacts/social) [sources] [site]
Contacts, Facebook, Twitter, Buzz, Linkedin 
- Twitter4J (social) [sources] [site]
Twitter API 
- android-wheel (UI) [sources] [site]
Android Picker Widget like Iphone 
- CommonsWare Android Components - CWAC (utility / UI) [sources] [site]
Open source libraries to help solve various tactical problems with Android development 
- libs-for-android (UI / feeds / image loader / utility) [sources] [site]
This project hosts a collection of open source libraries for the Android platform, including: 
- android-mapviewballoons (maps) [sources] [site]
Simple information balloon annotation for Android MapView 
- osmdroid (maps) [sources] [site]
OpenStreetMap-Tools for Android 
- libgdx (games) [sources] [site]
Android/desktop game development framework 
- forget3d (games) [sources] [site]
A OpenGL ES  Game framework 
- min3d (games) [sources] [site]
A 3d library/framework for Android using Java and OpenGL ES 
- Angle (games) [sources] [site]
project is aimed to be a way to develop 2D games using OpenGL ES on Android providing as much speed as possible. 
- AndEngine (games) [sources] [site]
AndEngine - Free Android 2D OpenGL Game Engine 
- Moai (games)[site]
The mobile platform for pro game developers (Lua Dev) 
- Corona(Games) [site]
Complete environment for developing across platforms 
- JMonkey Engine (Games) [site]
Java openGL Game Engine 
- Unity3D(Games)[site]
Unity 3 is a game development tool that has been designed to let you focus on creating amazing games.