Overview of higher education institutions
You can find Polish accredited higher education institutions on the website of Rad-on. This site is in Polish, but it is easy to search for the name of the institution (nazwa instytucji) or the type of institution (rodzaj instytucji), for example.
The website of NAWA (Polish National Agency for Academic Exchange) contains overviews of accredited Polish higher education institutions. They are categorised by type of institution. However, there are 14 types in total so it is sometimes a bit difficult to find them. The website is in English.