Darktable - darktable is an open source photography workflow application and raw developer.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
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.
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively for Mac.
GIMP - GIMP is a multiplatform photo manipulation tool.
Sumo Paint - Photoshop in your browser, Sumo Paint an advanced browser-based image editor.