IcoFX might be a bit more popular than Autodesk SketchBook. We know about 1 link to it since March 2021 and only 1 link to Autodesk SketchBook. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Try sketchbook.com, the official site. I don't know if it's different from the Microsoft store version, but it might be. There should be a free trial. Source: over 2 years ago
If you're looking for an icon editor, there are many available, such as IconWorkshop, Icofx, and Iconion, but I haven't tried any of those. Source: 11 months ago
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.
IconsExtract - Extract icons and cursors stored in EXE, DLL, OCX, CPL files
Procreate - Procreate is the most powerful and intuitive digital illustration App available for iPad®.
IconWorkshop - Application to create and manage software icons. A must for developers.
ibis Paint X - Drawn with + ibisPaint
IconLover - Icon editor for Windows.