There’s a few subs designed for that as well:
This is a great way to find servers, but I don’t see how i can use it to find specific communities. Let’s say I wanted to see if a community has been created that discusses the book series The Wheel of Time. Is there a good way to look for this, within all the servers?
You could search on https://browse.feddit.de - but it would depend what name had been given to the community (if one exists of course)
Had a look myself, and there is https://lemmy.ml/c/wheeloftime :-)