Search over 1.1 million distinct spatial WMS, WFS, WCS, and WMTS layers hosted on 110,000 services from around the world. 

Search Tips
British Columbia or geology Australia or rivers Asia- Search spatially. 
tree preservation 27700 - Include an EPSG code to prefer results in that projection. 
arbol Spain - Not all layers are in English, try the official language. 
wcs Germany chart - Search for a specific service (wcs, wmts, wfs, wms).  We'd suggest only including one service in a search. 
York -"New York" - Standard search features are supported too.  Exact phrase searching (wrap with ") and exclude (prefix with -)
wms (Alps | Himalayas) - Boolean logic - by default GeoSeer puts an AND between all your search terms meaning all terms are mandatory in the result.  You can use OR (with the pipe: | ) instead to expand the search results, and brackets () for grouping.