There are plenty of other tile servers you can choose from, free or paid. Most provide a static tile service/API, usually called Static Tiles or just Tile Requests (if no vector tiles are supported).
A good catalogue of servers (usually called Providers elsewhere) can be found at the websites below:
Switch2OSM also provides detailed instructions on how to serve your own tiles: this can be surprisingly economical and enjoyable if you don't mind a few hours in a Linux console. However, this will require a very high-spec computer, especially for larger areas, and hosting this might be more complicated than it's worth.