Krita is a free and open-source digital painting application designed for both amateur and professional artists. It is available for Windows, Linux, and macOS. Krita is packed with features and tools to help you create digital art, illustrations, and concept art. It includes a wide range of brushes, filters, and layers to help you create unique artwork. Krita also includes a layer system to help you better organize your work. Additionally, Krita includes a range of tools to help you create and manipulate shapes, 3D objects, and textures. It also supports a variety of file formats and supports high-resolution printing. Krita is designed for both beginners and experienced digital artists and has a friendly user interface.
Both programs aim at simplicity / usability.