GroupMe is a group chat app that allows you to organize the conversations you have with your friends. With the app you can arrange messages by specific groups / topics so one group has your conversations about basketball, the other about politics, another for your travels and so on.
Dubsmash from Mobile Motion is a simple messaging program that allows you to make short selfie video records and share them with your friends. Messages can be sent in single one on one or group threads, and each one can have videos and text, and what makes this unique is you can choose from a number of famous quotes and dub yourself over them, which can be pretty funny.
Social and chat apps are pretty common, but WeChat from Tencent Technology has many features that set it apart from the rest. With this app all your communication tools like messages, images and video calls are stored in one place, and all you need to do is create a user ID and you are set to go. The interface is quite intuitive so it's easy to figure out what to do, and there are no ads too.