A self-hosted URL shortener: Shlink - Keep control over all your shortened URLs, by serving them under your own domains, using this simple yet powerful tool. https://shlink.io/
I was very surprised to find this mature, full-featured URL shortener. It's written in PHP and includes Geoblocking so your shortener isn't abused.
A Docker quick-start guide: https://lnk.clifmo.com/ljk13
TLDR: Audiobookshelf
Been selfhosting it for a few years. Audible is an interesting comparison and I agree with the author that ABS is superior. But it's not without its issues and challenges. Any good podcast app has vastly superior UX. That said, I'm a hoarder and I just have to store every podcast I subscribe to for some reason.