Color loads of pixelated pictures by number with the app UNICORN. Just choose a beautiful picture and start coloring! And, the app saves your progress, so you can take a break whenever you'd like and finish your picture later. The coloring system of UNICORN is very simple: there's a palette of colors on the bottom of the screen, each one with a corresponding number. Just tap a color, and then tap all the spaces labeled with its number to start coloring. While working on a picture, you can pinch the screen to zoom in or out to comfortably see the drawing no matter where you're coloring. Exit any picture, and your progress will be perfectly saved. This way, you can leave a drawing and return to it later, as well as color multiple drawings at the same time. UNICORN is a great color-by-number app, with more than a dozen pictures to color. If you want access to all the drawings (and there are TONS), you'll have to pay the app's monthly fee.
Android 4.4 or higher required