Filterloop - Filterloop is a fantastic photo editing application offering millions of effects to make your photo look beautiful and attractive.
Aseprite - Aseprite is an art program dedicated to the creation of pixel art.
RNI Films - Real film filters for iPhone photographers
Pixel Art Studio - A purpose-built drawing tool for pixel artists
KD Pro - KD Pro is a fantastic camera application that captures photos in the same way as taken with a real disposable camera.
Piskel - Piskel is a website where designers online create sprites or pixel art.