I use Snapseed on Android. It's a practical app with many photo editing tools
I like how I can edit my photos here,
Manual Camera for iPhone - Custom exposure for your iPhone camera
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 .
Focus - New Tab page that gives you a moment of calm and inspires you to be more productive.
PicsArt - Explore 100,000,000+ awesome images and photos on the web
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Camera+ - With Camera+ you’re able to use your iPhone to shoot the best photos you possibly can.