I have always liked gamebooks with interesting game mechanics (not so much the traditional CYOA or Fighting Fantasy) and one great source for that in the past was the annual Windhammer Prize for Short Gamebook Fiction that ran from 2008-2015. I believe all the books are still available for download. Many interesting experiments there and I really enjoyed some books (but it was a while ago and I can't name any of my favorites now).

https://www.arborell.com/windhammer_prize.html

The Lindenbaum Compatition is a newer attempt to do something similar and it has also resulted in some books that I enjoyed reading/playing several of the books from the first year (have not taken the time to look into the entries this year):

https://www.lloydofgamebooks.com/p/voting-is-open-for-202420...