Drawasaurus - Drawasaurus is an online drawing & guessing game you can play with friends or strangers.
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
LetsDraw.It - Guess and Draw, Drawing Battle, Pictionary, Copy picture - online drawing games where you can compare your skill with others.
Artrage - A simple but lovely natural media painting and sketching program.
gartic.io - Draw, guess, and win!
Procreate - Procreate is the most powerful and intuitive digital illustration App available for iPad®.