http://3cbzkrvakrpetjjppdwzbzqrlkmzatjs7jbyazap5gwutj32gcltjpqd.onion
Some aggressively defederate with instances known to harbor poisonous people; some don’t. And, to harken back to the BBS era, if you have some time, some skill, and a few bucks, you can run your own Mastodon instance. Personally, I still visit Facebook on occasion because some people I care about are mainly there.