Astropad - Astropad is a free form drawing tool designed from the ground up to take advantages of the features offered by an iPad.
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.
Paper by WeTransfer - A collection of creative prompts
Autodesk SketchBook - SketchBook drawing and painting software provides designers, architects, and concept artists the tools to sketch ideas quickly and create beautiful illustrations.
Milanote - Milanote is a note taking app for creative work.
Clip Studio Paint - The artist's software for drawing and painting.