Free Software for Android
Google Keep
A free note-taking service developed by Google. With Google Keep you can quickly capture what's on your mind and get reminded at the right time or place. Google Keep is available on the web, and has mobile apps for the Android and iOS mobile operating systems. You can use your original Google Account, email or phone to access your notes stored in Google's cloud.
Kik
Kik is a free instant messaging and social networking app that allows you to stay connected with friends and stay in the loop. Over 4 million people use Kik on their smartphones to send messages and connect with the world around them. The design of the Kik application is easy on the eyes, and even easier to use. Share emojis and images directly in the chat and create and interact with chatbots to perform task like enhancing images, get news or play simple games.
Perkeep
Perkeep is a set of free and open-source formats, protocols, and software for modeling, storing, searching, sharing and synchronizing data in the post-PC era. Data may be files or objects, tweets or 5TB videos, and you can access it via a phone, browser or FUSE filesystem. Perkeep is openly and actively developed and anyone is free the contribute to the project.
Todo.txt
With Todo.txt you can track your performance in a simple text file. Todo.txt provides a simple and intuetive text-based user interface that can be used in-application or in a command line tool of your choice. With a simple but powerful shell script called todo.sh, you can interact with todo.txt at the command line for quick and easy, Unix-y access.
Movim
Movim is a distributed social platform, with web client and mobile apps, that protects your privacy, comes with a set of awesome features and uses the industry-standard XMPP protocol.
Tripify
With Tripify you can discover the most amazing destinations, best things to do in each place, view photos, maps, reviews about each attraction, restaurant, park. The application also allow you to plan your trips step by step, bookmark what you find cool, search hotels, share what you enjoy along your journey.
Phoenix OS
Phoenix OS is an operating system specifcally designed to bring Android gaming to the PC. The OS is based on Android 7.1 and is developed and released free and open-source. With Phoenix OS you can play your Android games on a big screen, with mouse and keyboard support thanks to Octopus keymapping engine and Game Assistant, offering a powerful fundamental keymapping.
Imo
Imo is a free communication platform used by over 200 million people across the globe. Imo has clients for both desktop and mobile devices and lets you video chat with family and friends and meet new friends and share stories on the ImoZone. Imo can handle audio and video calls no matter if they are abroad or not.
WeChat
WeChat connects a billion people with voice calls, video calls, photo sharing, chats and payments. The multi-purpose application is developed by the Chinese company Tencent and is and in China, it is described as "the app for everything". WeChat is primarily developed for the mobile consumer, but is also avalible on desktop and in the browser.
Nextcloud
With Nextcloud, users can host their own secure cloud solution for file storage, collaboration and communication for enterprise or personal purposes. Nextcloud gives you full control over your own data and where and how you host it. The software can be hosted on-premise or on any VPS or cloud instance provided by third-party web hosts. If you value privacy and security, Nextcloud might be the right choice for you. Nextcloud is both free and open source and developed in an open, transparent and trustworthy manner.