I use Snapseed on Android. It's a practical app with many photo editing tools
I like how I can edit my photos here,
VSCO - VSCO® is an art and technology company empowering people everywhere to create, discover, and connect. CompanyVSCO® is a trendsetting art and technology company that .
Priime - Edit photos with the styles of the world's top photographers. Smart suggestions, fast editing, and inspiring collections.
PicsArt - Explore 100,000,000+ awesome images and photos on the web
Filters for iPhone - Transform your photos. 800+ filters and effects. Just 99¢.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Dubble - Take a picture and randomly mix it with anyone in the world