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.
malmal - Draw together on a nearly infinite canvas with your friends or with strangers.
Procreate - Procreate is the most powerful and intuitive digital illustration App available for iPad®.
DrawPile - Drawpile is a drawing program that lets you share the canvas with other users in real time.
ibis Paint X - Drawn with + ibisPaint
Aggie.io - Draw a picture together with your friends in real-time over the internet in your browser.