There are a couple of topic-based clients, https://zapddit.com and https://agorasocial.app , and nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z has opened a new NIP to discuss implementation of moderated communities on Nostr: https://github.com/nostr-protocol/nips/pull/602 . I’ll repost your note for more visibility too.