Happy mapbox customer here, but unfortunately I expect some of the longshot feature requests may never see the light of day now that outside development contrib

Happy mapbox customer here, but unfortunately I expect some of the longshot feature requests may never see the light of day now that outside development contributions are going to go to zero. Is there any OSS or economical (Non-ESRI; non-Google) commercial solution for WebGL maps and vector base layer that supports non-mercator projections without hacks? (Arbitrary projections, not just distorting mercator onto a spehere)