Making an excel spreadsheet to catalog all of my owned games. Now here I thought Steam might be the hardest, but when I finally finished it, I come to GOG, and am left scratching my head.

There is nowhere I can seem to find a copy and paste list of my games. Just a series of images. When I decide to look at it as list view, nothing can be highlighted. I thought maybe there would be some code imported to my wiki page from barefoot essentials at least showing the names of games, and it is a simple line of code, with no games listed.

now I could take the task of writing out each title, but I own over 500 games on GOG, and really want to avoid that.

Any suggestions?

https://www.gog.com/account/settings/orders
And try 3rd party download tools, like gogrepo.py or lgogdownloader.

You can use one of the tools provided by users. One thing I would say, and this should be in big letters with a flashing background:
Do not use Excel!!!

Sure, it's easy, and will seem great for ages. Then you will notice that at some point you have accidentally sorted wrong, or made a mistake, or need to do mass changes, or need to do data cleaning, and then you will have a total nightmare. I know I have been through it, cataloging a few is fine, but when you get up to thousands, even tens of thousands the metadata becomes far more important and difficult to work with. Use a database, I currently use gamecollector from collectorz. It is ok, though you pay once for a few years support, it all works ok, and keeps backups. I have been meaning to build my own using SQLite for some time now, but it's getting round to it. Other options I am looking into is myvisualdb:
http://myvisualdatabase.com/
Which seems simple and can create apps. But I really cannot say it enough, don't use excel.