I use Snapseed on Android. It's a practical app with many photo editing tools
I like how I can edit my photos here,
AndreaMosaic - With AndreaMosaic you can create your own photographic mosaics made with your own pictures.
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 .
Percolator - Percolator: the always fun, supremely unique photo app that is sure to surprise you! FEATURES:
PicsArt - Explore 100,000,000+ awesome images and photos on the web
WidsMob Montage - Make stunning mosaic photos or montage shape with tiles, which supports both JPEG and PNG files.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.