Below some great Android apps that you can use for working with your Raspberry Pi. All 5 Andriod apps are free to use and should work with the Raspbian operating system

1. RaspManager

This app enables you to view what is happing on your Pi. Overview of memory, CPU and network usage and start/stop services. You can take pictures when you have a camera module connected. The most interesting feature is to send / receive files from / to your phone / Pi.

https://play.google.com/store/apps/details?id=com.cea.raspmanager&hl=en

2. RaspiCam Remote

This app automatically scans your network for Pi so that you can connect and control your camera module. Take a picture or start recording a video with your phone. Also you can download and view the result in the App.

https://play.google.com/store/apps/details?id=com.pibits.raspberrypiremotecam&hl=en

3. Cayenne

This app automatically scans your network for Pi so that you can connect to it. Once Pi installation is completed you get a complete;y customizable dashboard with all the (GPOI) sensors available. This app is ideal to control your Pi with your phone.

https://play.google.com/store/apps/details?id=com.mydevices.cayenne&hl=en

4. Kodi Remote (Kore)

Many people use their Pi in their living room in combination with KODI (OpenElec). Want to start a video from your couch, this is the app to do it.

https://play.google.com/store/apps/details?id=org.xbmc.kore&hl=en

5. VNC Viewer

Last but not least: VNC Viewer app. This VNC client can be used to connect to Pi desktop. Can be a bit tricky to control with touch on smaller phones...

https://play.google.com/store/apps/details?id=com.realvnc.viewer.android&hl=en