There's not an easy way to "export" them but if you find the industry property under settings>properties it should show you the attributes for it including the options already defined.
I had the same issue. I painstakenly copied and pasted all the industries listed in Hubspot in to an Excel spreadsheet so that I could more easily update my Excel database before uploading to Hubspot. This list was created on August 31, 2019. Hope this is helpful!