here are two sites I have been linked recently:

https://lemmy.directory/communities/listing_type/All/page/1

https://browse.feddit.de/

The first one shouldn't be used as a directory. The second one, can be used.

The reason the first one can't, is because it is just the search directory of one instance. Each instance knows/shows a community only AFTER some user has indexed it manually by putting the full url of that federated community in the search bar and submitted it. Only after this, does lemmy.directory will be able to show it.

The admin from lemmy.directory actually stated that his instance tries to fetch all communities from everywhere in order to build a directory, it's not meant as an actual, general instance.