nostr:npub14yvwdyq02fq8ta9w7rqhtzlfep3v748ehk5rutq4cux862apepes0g6g3l
It depends on what you mean by "free speech": there's a whole body of discussion around what constitutes freedom of speech, and where its boundaries lie.

Liberdon is the only big one I can think of that isn't blocked by the rest of Fedi, because the mods enforce rules about hate speech / slurs and harassment.  You can go to servers that allow it, if that's what you really want, but it's a deal breaker for like 90% of users, so they're blocked by nearly everyone else.  Twitter also allows everything that doesn't offend Daddy Elon these days, but I wouldn't recommend Twitter to anyone.