The Ordnance Survey (UK) has a trial of Open Zoomstack, serving some of their Open Data layers as vector tiles via an API.

Being vector tiles, this means that the appearance of individual layers can be customised.

They have created four styles, here I use the 'outdoor' style they provide as a JSON file, but customise it by preventing any names from displaying, and not using the 'fill-extrusion' effect on the buildings layer.

This may be useful for applications such as overlaying data, or custom labels on the map, which can be done using Leaflet.js.