I've been looking for good examples for my next book, but everything I've read about has turned out to be not used, including everything in Michael Bader's book

I've been looking for good examples for my next book, but everything I've read about has turned out to be not used, including everything in Michael Bader's book [1], except for S2Geometry [2], but I feel like I need to talk to someone who has more expertise in the benefits/drawbacks of using that in an actual product. [1]: https://www.google.com/books/edition/Space_Filling_Curves/zmMBMFbia-0C?hl=en&gbpv=0 https://www.google.com/books/edition/Space_Filling_Curves/zm... [2]: https://github.com/google/s2geometry https://github.com/google/s2geometry