A Mastodon fork with some interesting features. Most notably "Local only posting" - posts that can only be seen by users on the local instance.
Intended to be used as a small social network for friends (that already have some social connection).
Run your own social
A guide by the developer of Hometown on how to run a small social network.
Party at My House: Darius Kazemi on Human-Scaled Social Media
Interview with developer in Logic.