However, because of the easy availability of MS Paint it's worth mentioning - if nothing else because it does have a basic toolkit that is expanded on by other software.
Microsoft Paint is a basic art package that comes with every Windows install, and has done so since at least Windows 3.x. The release of Windows 10 has seen 3D editing tools added to it, but let's be fair-it's still a simple program that isn't going to rival anything else on this list. However, because of the easy availability of MS Paint it's worth mentioning - if nothing else because it does have a basic toolkit that is expanded on by other software.