Damus was one of the first Nostr clients to hit Apple's App Store and remains one of the best-maintained. It is a Swift-native app with a clean feed, zaps, DMs, and long-form reader. The open-source repo tracks active Nostr protocol work closely.
The App Store listing has survived a Chinese-market takedown and returned, which made Damus a minor symbol of what censorship-resistant social media actually looks like in practice.