Sticker Studio!
WhatsApp featured stickers on their platform just last month, and offered a package that was previously available on Facebook Messenger. But if you're on Android, you can easily create 'stickers' yourself on your phone. This is thanks to Sticker Studio, a free app, built by Sven van der Zee, a former developer in TNW.
You can put pictures or import images, and simply draw a part around the object you want to transform into a sticker.
There are some strange limitations: you will need to create at least three stickers before exporting a bundle of them to WhatsApp. You are limited to 10 packages with a maximum of 30 stickers per package.
Anyhow, it is very entertaining for those who have energetic people in their lives. That's all you can do now; Sticker Studio currently does not allow you to change images or add effects - but these features are under development.
The app is on Google Play and can be downloaded free of charge.