Connecting to WMS (Web Map Service), WFS (Web Feature Service), and WCS (Web Coverage Service) servers
All these are web service standards from the Open Geospatial Consortium (OGC) that allow web clients to query and receive geographic information in the form of image, vector, or coverage data.
Some organizations that offer such services are:-
1~ USGS: https://mrdata.usgs.gov/wms.html
2~ Boundless Geo: https://demo.boundlessgeo.com/geoserv...
3~ Mundialis: https://www.mundialis.de/en/ows-mundi...
4~ Terrestris: http://ows.terrestris.de/dienste.html...
5~ Geofabrik: http://wms.geofabrik.de/
6~ The Hug: https://www.the-hug.co.uk/mapping/til...
7~ Omniscale: https://maps.omniscale.com/en/
8~ WhereGroup: https://www.wheregroup.com/de/osmwms
9~ Sinica: http://gis.sinica.edu.tw/worldmap/wmts