SPARQL Endpoint Status is a project developed to monitor the availability, performance, interoperability and discoverability of public SPARQL endpoints. There is an instance of it hosted by the Vienna University of Economics and Business here.
This instance contains mutiple years' worth of data on SPARQL endpoints which are registered on datahub.io. As of February 2022, 109 of 565 tracked endpoints were marked as available and operating normally. However, some of these endpoints are simply different-language versions of other endpoints, or versions of the same dataset across multiple institutions.
Regardless, this list is useful for filtering out endpoints which do not even respond to requests.
The following is a curated list of endpoints which we used during our research. These endpoints are confirmed to be fully functional and available, and they contain meaningful data.
https://data.gov.cz/sparql https://dev.nkod.opendata.cz/sparql
https://linked.opendata.cz/sparql
Dataset of people, papers, organizations and conferences within the linked data sphere.
http://www.scholarlydata.org/sparql/
Registry of land identification, addresses and properties in the Czech Republic
https://ruian.linked.opendata.cz/sparql
http://linkedgeodata.org/sparql
https://semantic.eea.europa.eu/sparql
https://environment.data.gov.uk/sparql/bwq/query https://environment.data.gov.uk/bwq/sparql.html