I use Snapseed on Android. It's a practical app with many photo editing tools
I like how I can edit my photos here,
Filtron - Create and share your own photo filters on Mac & iPhone
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 .
Web Photo Filter - A web component to apply Instagram-like filters to photos
PicsArt - Explore 100,000,000+ awesome images and photos on the web
CSSGram - Recreate Instagram filters with CSS filters and blend mode
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.