“Openbare scholen” best translated as public schools are non-religious schools. They are open to every type of student, education is not based on religious grounds.
https://janhekmanschool.nl/
https://www.dezwaluw.nl/
https://www.kindercampusking.nl/
https://www.obs-michielderuyter.nl/
https://www.obs-piethein.nl/
https://www.obsdepioniers.nl/
https://westwijzer.nl/