(also an interesting approach so site search)

MrBotchi is federated microblogging platform for single-user.

Grid layout, pinned contents, works for microblogging as well as blog posts & images posts.. maybe the closest thing to a decentralised Tumblr so far?

Epicyon is an AGPL licensed ActivityPub protocol compliant federated social network server suitable for hosting a small number of accounts on low power systems requiring minimal maintenance, such as single board computers. It's the ActivityPub equivalent of an email server, storing posts as human readable JSON on file, rather than in a database. It also uses only a small amount of RAM.