Is it only through TOR?
SimpleX, and with a nostr:npub126ntw5mnermmj0znhjhgdk8lh2af72sm8qfzq48umdlnhaj9kuns3le9ll server you can self-host the communication on your own server as well.
Discussion
Yes, but nostr:npub126ntw5mnermmj0znhjhgdk8lh2af72sm8qfzq48umdlnhaj9kuns3le9ll is working on clearnet integration for their services. Not 100% sure if clearnet would also apply for SimpleX.