Hi abraxas86 and thanks a lot for this script ! I was looking such a solution and you've done it.
Just tested it, it works like a charm.
The major need is to have a nice way to manage collections as it is not yet possible on Itch. With your script, any Webdev could do its own work upon it and do what they want. As I want to do also.
I looked how the data is pulled from Itch and yes, it's all HTML from the request and the API does not permit this kind of access (like JSON results as we'd like to have). BUT there are fetch requests like these ones : https://itch.io/my-collections/more-games/9211?page=2 that bring the same HTML that you parse in your Tampermonkey script, so your script could probably be updated to automatically get all the collections in one click ! Yes, it's more work to do. I'm not asking you to code it, it's definitely something I or someone else can try too.
Ideally, an Electron app (or even a Website) could to the job :p (again I'm not asking you to make it ^^). So the app could be shared to every Itch user.
Your script is a very good start and job !
I'll keep you informed if I work on it.
Edit : For a standalone app, I realise the credentials thing could be tricky to manage as the collection URL is not part of the API. Perhaps using the OAuth login we could make requests with the logged user, not sure, to be continued...