A free program for Android, by Color by Number: Pixel Art by Peaksel.
This is a coloring book for adults. The app is based on the concept of “paint by number”. You can choose from a variety of categories such as animals, birds, fish, robots, vehicles, and many more. The images are of high quality and come in a variety of sizes.
You can select from a variety of colors. Each color will give you a specific effect. You can also utilize an assortment of backgrounds, such as the beach, the forest, or the city.
The app is very easy to use. Just open it, choose the image you want, and start painting. You will be given the number of the color you have to use. You will be able to choose from a variety of tools such as a paint brush, a pencil, a pen, a roller, a comb, and many more.