I run https://mapchart.net .

It is a simple tool that lets you create custom maps of the World, USA, Europe, UK, France and more. I treat is as a side-project, but I am constantly adding new maps or expanding some features.

The biggest advantage is that it costs almost nothing to maintain it, as it is completely client-side, so the only cost is the basic hosting plan. I launched it almost 2 years ago and right now it is the no.1 search result for queries related to creating maps and gets an occasional boost from Reddit posts or other blogs.