Write Freely is free and open source software for starting a minimalist, federated blog - or an entire community.
WriteFreely is just about writing – everything is built around plain text / Markdown, and keeping everything as simple as possible. Federation is basically one-way right now
Federated blogging application, thanks to ActivityPub
Plume is trying to be more on-par with Medium, with reading and writing all built-in. It supports more of ActivityPub, including comments, likes, and boosts.