Just run the following JavaScript bookmarklet on https://www.microsoft.com/en-us/software-download/windows10 to reveal all Windows versions.
$("select#product-edition").html("<option value selected value='selected'>Select edition</option><option value='2'>Windows 7 Home Basic SP1 </option><option value='4'>Windows 7 Professional SP1 </option><option value='6'>Windows 7 Home Premium SP1 </option><option value='8'>Windows 7 Ultimate SP1 </option><option value='10'>Windows 7 Home Premium N SP1 </option><option value='12'>Windows 7 Professional N SP1 </option><option value='14'>Windows 7 Ultimate N SP1 </option><option value='16'>Windows 7 Professional K SP1 </option><option value='18'>Windows 7 Professional KN SP1 </option><option value='20'>Windows 7 Home Premium K SP1 </option><option value='22'>Windows 7 Home Premium KN SP1 </option><option value='24'>Windows 7 Ultimate KN SP1 </option><option value='26'>Windows 7 Ultimate K SP1 </option><option value='28'>Windows 7 Starter SP1 </option><option value='48'>Windows 8.1 Single Language </option><option value='52'>Windows 8.1 </option><option value='55'>Windows 8.1 N </option><option value='61'>Windows 8.1 K </option><option value='62'>Windows 8.1 KN </option><option value='68'>Windows 8.1 Professional LE </option><option value='69'>Windows 8.1 Professional LE K </option><option value='70'>Windows 8.1 Professional LE KN </option><option value='71'>Windows 8.1 Professional LE N </option><option value='75'>Windows 10 Education (Academic) - build 10240</option><option value='76'>Windows 10 Education KN (Academic) - build 10240</option><option value='77'>Windows 10 Education N (Academic) - build 10240</option><option value='78'>Windows 10 China Get Genuine Chinese Simplified - build 10240</option><option value='79'>Windows 10 Pro-Home - build 10240</option><option value='80'>Windows 10 ProKN-HomeKN - build 10240</option><option value='81'>Windows 10 ProN-HomeN - build 10240</option><option value='82'>Windows 10 Single Language - build 10240</option><option value='83'>Windows 7 Home Basic SP1 COEM </option><option value='85'>Windows 7 Home Basic SP1 COEM GGK </option><option value='86'>Windows 7 Home Premium N SP1 COEM </option><option value='87'>Windows 7 Home Premium SP1 COEM </option><option value='88'>Windows 7 Home Premium SP1 COEM GGK </option><option value='89'>Windows 7 Home Premium K SP1 COEM </option><option value='90'>Windows 7 Professional N SP1 COEM </option><option value='91'>Windows 7 Professional SP1 COEM </option><option value='92'>Windows 7 Starter SP1 COEM </option><option value='93'>Windows 7 Ultimate K SP1 COEM </option><option value='94'>Windows 7 Ultimate KN SP1 COEM </option><option value='95'>Windows 7 Ultimate N SP1 COEM </option><option value='96'>Windows 7 Ultimate SP1 COEM </option><option value='97'>Windows 7 Home Premium KN SP1 COEM </option><option value='98'>Windows 7 Professional KN SP1 COEM </option><option value='99'>Windows 10 Pro-Home - build 10586 </option><option value='100'>Windows 10 Education - build 10586 </option><option value='101'>Windows 10 Education KN - build 10586 </option><option value='102'>Windows 10 Education N - build 10586 </option><option value='103'>Windows 10 China Get Genuine Chinese Simplified - build 10586</option><option value='104'>Windows 10 ProKN-HomeKN - build 10586 </option><option value='105'>Windows 10 ProN-HomeN - build 10586 </option><option value='106'>Windows 10 Single Language - build 10586 </option><option value='107'>Windows 10 IoT Core Insider Preview - Build 10586 </option><option value='108'>Windows 10 IoT Core Insider Preview - Build 14262 </option>");
Doesn't work anymore.