I had to work around daytime bandwidth caps for a couple years so being able to download content overnight was pretty handy.

Tube Archivist is “Your self hosted YouTube media server”. I follow several youtube channels and so this will automatically fetch videos and serve them locally which is great. - https://www.tubearchivist.com/

On a similar note LanCache is also handy at providing a local cache for Steam and Windows Updates when you have several PCs on the same network - https://lancache.net/

Pi-hole is a popular DNS based ad-blocker that can cut down on some ads and trackers - https://pi-hole.net/