Link preview, it's the first few lines of the video's description. Guess they're one of the growing number of channels that uses it to advertise rather than describe.
One of my favorite Sanderson books period. In fact, while I don't want to state it too definitively because recency bias is real, I think this may very well be his best individual book to date (it's hard to fairly compare a series to a single novel though). Everything about it was so well-done, I wish I knew more about the behind-the-scenes of storytelling so I could compliment it properly.
There is one other story I know of which has been partially released, The Eyes (a precursor to Skyward), about fifteen pages of which were posted to the Writing Excuses Patreon. However, in addition to feeling kind of iffy about pointing people to paying $10 for a very small sample from a very rough draft, the tier the file was attached to does not actually exist anymore, so I'm not sure whether subscribing even will give it to you now or not. As such, I've left it off the list.
Painter's world for me. It's just such a vibe, I don't know what else to say.