AFAIK, yes, I've only found those two as well. I think Snarfed hasn't released his own bridge yet.
Also, as an aside, there was an issue about Nostr bridges.
Mostr was blocked by mastodon.social citing lack of moderation in #Nostr land.
But haven't blocked Momostr [yet]?
Then there was a Bluesky Nostr spam that was blamed on Mostr but actually came from Momostr.
Anyway, found the explanation by Mostr here: https://njump.me/nevent1qqspyexvgpgakkd0ngsl0lgqrl04yy6zfa2ca2dtz6smq98u5gjs4agzyp478ruvv00hm0uymdlvffhxlw7c6xwu5wucpmadrpv9c3hsfvn0j0jvyw0
Ryan Barrett (npub1qal…csz4)