You can try out this one for yourself by using the link: All in all this site has a large amount of world building features. There are even more tools like the random dungeon generator, inn generator, and even town generator.
On top of the Fractal World Generator on their site, the site contains a fantasy name generator, calendar generator, a secondary world generator that utilizes different tools from the fractal world generator and places names and hex grids on top the maps that it generates. Check out my most recent creation using this generator. Color can also be changed on the map as well but I personally like the default Atlas theme for the map that they have and I usually always use the square setting. With this map generator Dungeon Masters are able to change the shape of the map as well as dictate the amount of water to land and ice to land. The one I use the most from this site is the Fractal World Generator. Donjon is an incredible site that has all sorts of world building tools.