LINQPad hosted wiki
I was just looking back at the old Stack Overflow post listing out a lot of the extension methods:
https://stackoverflow.com/questions/3555317/linqpad-extension-methods
Considering the leadership's direction with the site, I'm not confident the post (and site 😖) will be around for much longer.
Have you considered adding a wiki to have a more official "guide" and documentation?
I'm not volunteering myself to manage it, but I would definitely make some contributions. Info in posts like that wouldn't be lost and if there's enough interest, we can help keep it up to date.